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Glass is a non-
crystalline A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
, often
transparent Transparency, transparence or transparent most often refer to: * Transparency (optics), the physical property of allowing the transmission of light through a material They may also refer to: Literal uses * Transparency (photography), a still, ...
,
amorphous solid In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid, glassy solid) is a solid that lacks the long-range order that is characteristic of a crystal. Etymology The term comes from the Greek ''a'' ("wi ...
that has widespread practical, technological, and decorative use in, for example,
window A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent mat ...
panes,
tableware Tableware is any dish or dishware used for setting a table, serving food, and dining. It includes cutlery, glassware, serving dishes, and other items for practical as well as decorative purposes. The quality, nature, variety and number of o ...
, and
optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultrav ...
. Glass is most often formed by rapid cooling (
quenching In materials science, quenching is the rapid cooling of a workpiece in water, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as pha ...
) of the
molten Melting, or fusion, is a physical process that results in the phase transition of a substance from a solid to a liquid. This occurs when the internal energy of the solid increases, typically by the application of heat or pressure, which inc ...
form; some glasses such as
volcanic glass Volcanic glass is the amorphous solid, amorphous (uncrystallized) product of rapidly cooling magma. Like all types of glass, it is a state of matter intermediate between the closely packed, highly ordered array of a crystal and the highly disorde ...
are naturally occurring. The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...
(silicon dioxide, or
quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
), the primary constituent of
sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...
.
Soda–lime glass Soda–lime glass, also called soda–lime–silica glass, is the most prevalent type of glass, used for windowpanes and glass containers (bottles and jars) for beverages, food, and some commodity items. Some glass bakeware is made of soda-lime ...
, containing around 70% silica, accounts for around 90% of manufactured glass. The term ''glass'', in popular usage, is often used to refer only to this type of material, although silica-free glasses often have desirable properties for applications in modern communications technology. Some objects, such as drinking glasses and
eyeglasses Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples or ...
, are so commonly made of silicate-based glass that they are simply called by the name of the material. Despite being brittle, buried silicate glass will survive for very long periods if not disturbed, and many examples of glass fragments exist from early glass-making cultures. Archaeological evidence suggests glass-making dates back to at least 3,600 BC in
Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...
,
Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...
, or Syria. The earliest known glass objects were
beads A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under ...
, perhaps created accidentally during
metalworking Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scal ...
or the production of
faience Faience or faïence (; ) is the general English language term for fine tin-glazed pottery. The invention of a white pottery glaze suitable for painted decoration, by the addition of an oxide of tin to the slip of a lead glaze, was a major a ...
. Due to its ease of
formability Formability is the ability of a given metal workpiece to undergo plastic deformation without being damaged. The plastic deformation capacity of metallic materials, however, is limited to a certain extent, at which point, the material could experienc ...
into any shape, glass has been traditionally used for vessels, such as bowls,
vase A vase ( or ) is an open container. It can be made from a number of materials, such as ceramics, glass, non-rusting metals, such as aluminium, brass, bronze, or stainless steel. Even wood has been used to make vases, either by using tree species ...
s,
bottle A bottle is a narrow-necked container made of an impermeable material (such as glass, plastic or aluminium) in various shapes and sizes that stores and transports liquids. Its mouth, at the bottling line, can be sealed with an internal stop ...
s, jars and drinking glasses. In its most solid forms, it has also been used for
paperweights A paperweight is a small solid object heavy enough, when placed on top of papers, to keep them from blowing away in a breeze or from moving under the strokes of a painting brush (as with Chinese calligraphy). While any object, such as a stone, ...
and
marbles A marble is a small spherical object often made from glass, clay, steel, plastic, or agate. They vary in size, and most commonly are about in diameter. These toys can be used for a variety of games called ''marbles'', as well being placed in mar ...
. Glass can be coloured by adding metal salts or painted and printed as
enamelled glass Enamelled glass or painted glass is glass which has been decorated with vitreous enamel (powdered glass, usually mixed with a binder) and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or o ...
. The
refractive In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomeno ...
,
reflective Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The ' ...
and transmission properties of glass make glass suitable for manufacturing optical lenses,
prism Prism usually refers to: * Prism (optics), a transparent optical component with flat surfaces that refract light * Prism (geometry), a kind of polyhedron Prism may also refer to: Science and mathematics * Prism (geology), a type of sedimentary ...
s, and
optoelectronics Optoelectronics (or optronics) is the study and application of electronic devices and systems that find, detect and control light, usually considered a sub-field of photonics. In this context, ''light'' often includes invisible forms of radiat ...
materials. Extruded glass fibres have application as
optical fibres An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means t ...
in communications networks, thermal insulating material when matted as glass wool so as to trap air, or in
glass-fibre Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clot ...
reinforced plastic (
fibreglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...
).


Microscopic structure

The standard definition of a ''glass'' (or vitreous solid) is a solid formed by rapid melt
quenching In materials science, quenching is the rapid cooling of a workpiece in water, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as pha ...
. However, the term "glass" is often defined in a broader sense, to describe any non-crystalline ( amorphous) solid that exhibits a glass transition when heated towards the liquid state. Glass is an
amorphous solid In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid, glassy solid) is a solid that lacks the long-range order that is characteristic of a crystal. Etymology The term comes from the Greek ''a'' ("wi ...
. Although the atomic-scale structure of glass shares characteristics of the structure of a
supercooled liquid Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its melting point without it becoming a solid. It achieves this in the absence of a seed crystal or nucleus around which a crystal ...
, glass exhibits all the mechanical properties of a solid. As in other
amorphous solid In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid, glassy solid) is a solid that lacks the long-range order that is characteristic of a crystal. Etymology The term comes from the Greek ''a'' ("wi ...
s, the atomic structure of a glass lacks the long-range periodicity observed in crystalline solids. Due to
chemical bonding A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules and crystals. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing o ...
constraints, glasses do possess a high degree of short-range order with respect to local atomic
polyhedra In geometry, a polyhedron (plural polyhedra or polyhedrons; ) is a three-dimensional shape with flat polygonal faces, straight edges and sharp corners or vertices. A convex polyhedron is the convex hull of finitely many points, not all on ...
. The notion that glass flows to an appreciable extent over extended periods of time is not supported by empirical research or theoretical analysis (see viscosity in solids). Though a material viscosity on the order of 1017–1018 Pa s can be measured in glass, such a high value reinforces the fact that glass would not change shape appreciably over even large periods of time.


Formation from a supercooled liquid

For melt quenching, if the cooling is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead the disordered atomic configuration of the supercooled liquid is frozen into the solid state at Tg. The tendency for a material to form a glass while quenched is called glass-forming ability. This ability can be predicted by the rigidity theory. Generally, a glass exists in a structurally
metastable In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system's state of least energy. A ball resting in a hollow on a slope is a simple example of metastability. If the ball i ...
state with respect to its
crystalline A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
form, although in certain circumstances, for example in
atactic Tacticity (from el, τακτικός, taktikos, "relating to arrangement or order") is the relative stereochemistry of adjacent chiral centers within a macromolecule. The practical significance of tacticity rests on the effects on the physical p ...
polymers, there is no crystalline analogue of the amorphous phase. Glass is sometimes considered to be a liquid due to its lack of a first-order
phase transition In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states o ...
where certain
thermodynamic Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of the ...
variables such as
volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). Th ...
,
entropy Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
and
enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant ...
are discontinuous through the glass transition range. The glass transition may be described as analogous to a second-order phase transition where the intensive thermodynamic variables such as the
thermal expansivity Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...
and
heat capacity Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K). Heat capacity ...
are discontinuous, however this is incorrect. The equilibrium theory of phase transformations do not hold for glass, and hence the glass transition cannot be classed as one of the classical equilibrium phase transformations in solids. Furthermore, it does not describe the temperature dependence of Tg upon heating rate, as found in differential scanning calorimetry.


Occurrence in nature

Glass can form naturally from volcanic magma. Obsidian is a common volcanic glass with high silica (SiO2) content formed when felsic lava extruded from a volcano cools rapidly.
Impactite Impactite is rock created or modified by one or more impacts of a meteorite. Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact. On Earth, impactites consist primarily o ...
is a form of glass formed by the impact of a meteorite, where
Moldavite Moldavite ( cs, vltavín) is a forest green, olive green or blue greenish vitreous silica projectile glass formed by a meteorite impact in southern Germany (Nördlinger Ries Crater) that occurred about 15 million years ago. It is a type of tekti ...
(found in central and eastern Europe), and
Libyan desert glass Libyan Desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of s ...
(found in areas in the eastern Sahara, the deserts of eastern Libya and western Egypt) are notable examples.
Vitrification Vitrification (from Latin ''vitreum'', "glass" via French ''vitrifier'') is the full or partial transformation of a substance into a glass, that is to say, a non- crystalline amorphous solid. Glasses differ from liquids structurally and glasses po ...
of
quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
can also occur when
lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
strikes
sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...
, forming hollow, branching rootlike structures called
fulgurite Fulgurites (), commonly known as "fossilized lightning", are natural tubes, clumps, or masses of sintered, vitrified, and/or fused soil, sand, rock, organic debris and other sediments that sometimes form when lightning discharges into ground. ...
s.
Trinitite Trinitite, also known as atomsite or Alamogordo glass, is the glassy residue left on the desert floor after the plutonium-based Trinity nuclear bomb test on July 16, 1945, near Alamogordo, New Mexico. The glass is primarily composed of arkosic sa ...
is a glassy residue formed from the desert floor sand at the
Trinity The Christian doctrine of the Trinity (, from 'threefold') is the central dogma concerning the nature of God in most Christian churches, which defines one God existing in three coequal, coeternal, consubstantial divine persons: God th ...
nuclear bomb test site. Edeowie glass, found in
South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
, is proposed to originate from
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...
grassland fires,
lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
strikes, or hypervelocity impact by one or several asteroids or
comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...
s. File:Lipari-Obsidienne (5).jpg, A piece of volcanic obsidian glass File:Moldavite Besednice.jpg,
Moldavite Moldavite ( cs, vltavín) is a forest green, olive green or blue greenish vitreous silica projectile glass formed by a meteorite impact in southern Germany (Nördlinger Ries Crater) that occurred about 15 million years ago. It is a type of tekti ...
, a natural glass formed by meteorite impact, from Besednice, Bohemia File:Fulgurites-algeria.jpg, Tube fulgurites File:Trinitite from Trinity Site.jpg,
Trinitite Trinitite, also known as atomsite or Alamogordo glass, is the glassy residue left on the desert floor after the plutonium-based Trinity nuclear bomb test on July 16, 1945, near Alamogordo, New Mexico. The glass is primarily composed of arkosic sa ...
, a glass made by the Trinity nuclear-weapon test File:Libyan Desert Glass.jpg,
Libyan desert glass Libyan Desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of s ...


History

Naturally occurring obsidian glass was used by Stone Age societies as it fractures along very sharp edges, making it ideal for cutting tools and weapons. Glassmaking dates back at least 6000 years, long before humans had discovered how to
smelt Smelt may refer to: * Smelting, chemical process * The common name of various fish: ** Smelt (fish), a family of small fish, Osmeridae ** Australian smelt in the family Retropinnidae and species ''Retropinna semoni'' ** Big-scale sand smelt ''Ath ...
iron. Archaeological evidence suggests that the first true synthetic glass was made in
Lebanon Lebanon ( , ar, لُبْنَان, translit=lubnān, ), officially the Republic of Lebanon () or the Lebanese Republic, is a country in Western Asia. It is located between Syria to Lebanon–Syria border, the north and east and Israel to Blue ...
and the coastal north Syria,
Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...
or ancient Egypt. The earliest known glass objects, of the mid-third millennium BC, were
beads A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under ...
, perhaps initially created as accidental by-products of
metalworking Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scal ...
( slags) or during the production of
faience Faience or faïence (; ) is the general English language term for fine tin-glazed pottery. The invention of a white pottery glaze suitable for painted decoration, by the addition of an oxide of tin to the slip of a lead glaze, was a major a ...
, a pre-glass vitreous material made by a process similar to glazing. Early glass was rarely transparent and often contained impurities and imperfections, and is technically faience rather than true glass, which did not appear until the 15th century BC. However, red-orange glass beads excavated from the Indus Valley Civilization dated before 1700 BC (possibly as early as 1900 BC) predate sustained glass production, which appeared around 1600 BC in Mesopotamia and 1500 BC in Egypt. During the
Late Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...
there was a rapid growth in
glassmaking Glass production involves two main methods – the float glass process that produces sheet glass, and glassblowing that produces bottles and other containers. It has been done in a variety of ways during the history of glass. Glass container ...
technology in
Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...
and
Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Ana ...
. Archaeological finds from this period include coloured glass ingots, vessels, and beads. Much early glass production relied on grinding techniques borrowed from
stoneworking Stonemasonry or stonecraft is the creation of buildings, structures, and sculpture using stone as the primary material. It is one of the oldest activities and professions in human history. Many of the long-lasting, ancient shelters, temples, m ...
, such as grinding and carving glass in a cold state. The term ''glass'' developed in the late
Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post- Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediter ...
. It was in the
Roman glass Roman glass objects have been recovered across the Roman Empire in domestic, industrial and funerary contexts. Glass was used primarily for the production of vessels, although mosaic tiles and window glass were also produced. Roman glass productio ...
making centre at
Trier Trier ( , ; lb, Tréier ), formerly known in English as Trèves ( ;) and Triers (see also names in other languages), is a city on the banks of the Moselle in Germany. It lies in a valley between low vine-covered hills of red sandstone in the ...
(located in current-day Germany) that the late-Latin term ''glesum'' originated, probably from a Germanic word for a
transparent Transparency, transparence or transparent most often refer to: * Transparency (optics), the physical property of allowing the transmission of light through a material They may also refer to: Literal uses * Transparency (photography), a still, ...
,
lustrous Lustre (British English) or luster (American English; see spelling differences) is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the Latin ''lux'', meaning "light", and generally ...
substance. Glass objects have been recovered across the Roman Empire in domestic,
funerary A funeral is a ceremony connected with the final disposition of a corpse, such as a burial or cremation, with the attendant observances. Funerary customs comprise the complex of beliefs and practices used by a culture to remember and respect ...
, and industrial contexts, as well as trade items in marketplaces in distant provinces. Examples of
Roman glass Roman glass objects have been recovered across the Roman Empire in domestic, industrial and funerary contexts. Glass was used primarily for the production of vessels, although mosaic tiles and window glass were also produced. Roman glass productio ...
have been found outside of the former
Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post- Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediter ...
in China, the
Baltics The Baltic states, et, Balti riigid or the Baltic countries is a geopolitical term, which currently is used to group three countries: Estonia, Latvia, and Lithuania. All three countries are members of NATO, the European Union, the Eurozone, ...
, the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
, and
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. The Romans perfected
cameo glass Cameo glass is a luxury form of glass art produced by cameo glass engraving or etching and carving through fused layers of differently colored glass to produce designs, usually with white opaque glass figures and motifs on a dark-colored backgroun ...
, produced by
etching Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal. In modern manufacturing, other chemicals may be used on other types ...
and carving through fused layers of different colours to produce a design in relief on the glass object. In
post-classical In world history, post-classical history refers to the period from about 500 AD to 1500, roughly corresponding to the European Middle Ages. The period is characterized by the expansion of civilizations geographically and development of trade ...
West Africa,
Benin Benin ( , ; french: Bénin , ff, Benen), officially the Republic of Benin (french: République du Bénin), and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, Burkina Faso to the nort ...
was a manufacturer of glass and glass beads. Glass was used extensively in Europe during the
Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
.
Anglo-Saxon glass Anglo-Saxon glass has been found across England during archaeological excavations of both settlement and cemetery sites. Glass in the Anglo-Saxon period was used in the manufacture of a range of objects including vessels, beads, windows and was ev ...
has been found across England during archaeological excavations of both settlement and cemetery sites. From the 10th century onwards, glass was employed in stained glass windows of churches and
cathedral A cathedral is a church that contains the '' cathedra'' () of a bishop, thus serving as the central church of a diocese, conference, or episcopate. Churches with the function of "cathedral" are usually specific to those Christian denominatio ...
s, with famous examples at
Chartres Cathedral Chartres Cathedral, also known as the Cathedral of Our Lady of Chartres (french: Cathédrale Notre-Dame de Chartres), is a Roman Catholic church in Chartres, France, about southwest of Paris, and is the seat of the Bishop of Chartres. Mostly con ...
and the
Basilica of Saint-Denis The Basilica of Saint-Denis (french: Basilique royale de Saint-Denis, links=no, now formally known as the ) is a large former medieval abbey church and present cathedral in the commune of Saint-Denis, a northern suburb of Paris. The building ...
. By the 14th century, architects were designing buildings with walls of stained glass such as
Sainte-Chapelle The Sainte-Chapelle (; en, Holy Chapel) is a royal chapel in the Gothic style, within the medieval Palais de la Cité, the residence of the Kings of France until the 14th century, on the Île de la Cité in the River Seine in Paris, France. ...
, Paris, (1203–1248) and the East end of Gloucester Cathedral. With the change in architectural style during the
Renaissance The Renaissance ( , ) , from , with the same meanings. is a period in European history The history of Europe is traditionally divided into four time periods: prehistoric Europe (prior to about 800 BC), classical antiquity (800 BC to AD ...
period in Europe, the use of large stained glass windows became much less prevalent, although stained glass had a major revival with
Gothic Revival architecture Gothic Revival (also referred to as Victorian Gothic, neo-Gothic, or Gothick) is an Architectural style, architectural movement that began in the late 1740s in England. The movement gained momentum and expanded in the first half of the 19th cent ...
in the 19th century. During the 13th century, the island of Murano,
Venice Venice ( ; it, Venezia ; vec, Venesia or ) is a city in northeastern Italy and the capital of the Veneto region. It is built on a group of 118 small islands that are separated by canals and linked by over 400 bridges. The isla ...
, became a centre for glass making, building on medieval techniques to produce colourful ornamental pieces in large quantities.
Murano glass Venetian glass () is glassware made in Venice, typically on the island of Murano near the city. Traditionally it is made with a soda–lime "metal" and is typically elaborately decorated, with various "hot" glass-forming techniques, as well as ...
makers developed the exceptionally clear colourless glass
cristallo Cristallo is a glass which is totally clear (like rock crystal), without the slight yellow or greenish color originating from iron oxide impurities. This effect is achieved through small additions of manganese oxide.R. W. Douglas: ''A history of ...
, so called for its resemblance to natural crystal, which was extensively used for windows, mirrors, ships' lanterns, and lenses. In the 13th, 14th, and 15th centuries, enamelling and gilding on glass vessels was perfected in Egypt and Syria. Towards the end of the 17th century, Bohemia became an important region for glass production, remaining so until the start of the 20th century. By the 17th century, glass in the Venetian tradition was also being produced in
England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
. In about 1675,
George Ravenscroft George Ravenscroft (1632 – 7 June 1683) was an English businessman in the import/export and glass making trades. He is primarily known for his work in developing clear lead crystal glass (also known as flint glass) in England. Personal life L ...
invented
lead crystal Lead glass, commonly called crystal, is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead glass contains typically 18–40% (by weight) lead(II) oxide (PbO), while modern lead crystal, historically als ...
glass, with
cut glass Cut glass or cut-glass is a technique and a style of decorating glass. For some time the style has often been produced by other techniques such as the use of moulding, but the original technique of cutting glass on an abrasive wheel is still u ...
becoming fashionable in the 18th century. Ornamental glass objects became an important art medium during the Art Nouveau period in the late 19th century. Throughout the 20th century, new mass production techniques led to widespread availability of glass in much larger amounts, making it practical as a building material and enabling new applications of glass. In the 1920s a mould-etch process was developed, in which art was etched directly into the mould, so that each cast piece emerged from the mould with the image already on the surface of the glass. This reduced manufacturing costs and, combined with a wider use of coloured glass, led to cheap glassware in the 1930s, which later became known as
Depression glass Depression glass is glassware made in the period 1929–1939, often clear or colored translucent machine-made glassware that was distributed free, or at low cost, in the United States and Canada around the time of the Great Depression. Depres ...
. In the 1950s, Pilkington Bros.,
England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
, developed the float glass process, producing high-quality distortion-free flat sheets of glass by floating on molten
tin Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...
. Modern multi-story buildings are frequently constructed with curtain walls made almost entirely of glass.
Laminated glass Laminated glass (LG) is a type of safety glass that holds together when shattered. In the event of breaking, it is held in place by a thin polymer interlayer, typically of polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), lonoplast polyme ...
has been widely applied to vehicles for windscreens. Optical glass for spectacles has been used since the Middle Ages. The production of lenses has become increasingly proficient, aiding
astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...
s as well as having other application in medicine and science. Glass is also employed as the aperture cover in many solar energy collectors. In the 21st century, glass manufacturers have developed different brands of
chemically strengthened glass Chemically strengthened glass is a type of glass that has increased strength as a result of a post-production chemical process. When broken, it still shatters in long pointed splinters similar to float glass. For this reason, it is not considered ...
for widespread application in
touchscreen A touchscreen or touch screen is the assembly of both an input ('touch panel') and output ('display') device. The touch panel is normally layered on the top of an electronic visual display of an information processing system. The display is ofte ...
s for
smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
s,
tablet computer A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being com ...
s, and many other types of
information appliance An information appliance (IA) is an appliance that is designed to easily perform a specific electronic function such as playing music, photography, or editing text. Typical examples are smartphones and personal digital assistants (PDAs). Inf ...
s. These include
Gorilla Glass Gorilla Glass is a brand of chemically strengthened glass developed and manufactured by Corning, now in its seventh generation. Designed to be thin, light and damage-resistant, the glass gains its surface strength, ability to contain flaws, and ...
, developed and manufactured by Corning, AGC Inc.'s
Dragontrail Dragontrail, manufactured by AGC Inc., is an alkali- aluminosilicate sheet glass engineered for a combination of thinness, lightness and damage-resistance, similar to Corning's proprietary Gorilla Glass. The material's primary properties are its ...
and
Schott AG Schott AG is a German multinational glass company specializing in the manufacture of glass and glass-ceramics. Headquartered in Mainz, Germany, it is owned by the Carl Zeiss Foundation. The company's founder and namesake, Otto Schott, is cre ...
's Xensation.


Physical properties


Optical

Glass is in widespread use in optical systems due to its ability to refract, reflect, and transmit light following
geometrical optics Geometrical optics, or ray optics, is a model of optics that describes light propagation in terms of '' rays''. The ray in geometrical optics is an abstraction useful for approximating the paths along which light propagates under certain circumstan ...
. The most common and oldest applications of glass in optics are as
lenses A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
,
window A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent mat ...
s,
mirror A mirror or looking glass is an object that reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the im ...
s, and
prism Prism usually refers to: * Prism (optics), a transparent optical component with flat surfaces that refract light * Prism (geometry), a kind of polyhedron Prism may also refer to: Science and mathematics * Prism (geology), a type of sedimentary ...
s. The key optical properties
refractive index In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...
,
dispersion Dispersion may refer to: Economics and finance * Dispersion (finance), a measure for the statistical distribution of portfolio returns * Price dispersion, a variation in prices across sellers of the same item *Wage dispersion, the amount of variat ...
, and transmission, of glass are strongly dependent on chemical composition and, to a lesser degree, its thermal history. Optical glass typically has a refractive index of 1.4 to 2.4, and an
Abbe number In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of ''V'' in ...
(which characterises dispersion) of 15 to 100. Refractive index may be modified by high-density (refractive index increases) or low-density (refractive index decreases) additives. Glass transparency results from the absence of
grain boundaries In materials science, a grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are two-dimensional defects in the crystal structure, and tend to decrease the electrical and thermal ...
which diffusely scatter light in polycrystalline materials. Semi-opacity due to crystallization may be induced in many glasses by maintaining them for a long period at a temperature just insufficient to cause fusion. In this way, the crystalline, devitrified material, known as Réaumur's glass
porcelain Porcelain () is a ceramic material made by heating substances, generally including materials such as kaolinite, in a kiln to temperatures between . The strength and translucence of porcelain, relative to other types of pottery, arises main ...
is produced. Although generally transparent to visible light, glasses may be
opaque Opacity or opaque may refer to: * Impediments to (especially, visible) light: ** Opacities, absorption coefficients ** Opacity (optics), property or degree of blocking the transmission of light * Metaphors derived from literal optics: ** In lingu ...
to other wavelengths of light. While silicate glasses are generally opaque to
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
wavelengths with a transmission cut-off at 4 μm, heavy-metal fluoride and
chalcogenide : 220px, Cadmium sulfide, a prototypical metal chalcogenide, is used as a yellow pigment. A chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. Although all group 16 elements ...
glasses are transparent to infrared wavelengths of up to 7 and up to 18 μm, respectively. The addition of metallic oxides results in different coloured glasses as the metallic ions will absorb wavelengths of light corresponding to specific colours.


Other

In the manufacturing process, glasses can be poured, formed, extruded and molded into forms ranging from flat sheets to highly intricate shapes. The finished product is brittle and will fracture, unless
laminated Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materia ...
or tempered to enhance durability. Glass is typically inert, resistant to chemical attack, and can mostly withstand the action of water, making it an ideal material for the manufacture of containers for foodstuffs and most chemicals. Nevertheless, although usually highly resistant to chemical attack, glass will corrode or dissolve under some conditions. The materials that make up a particular glass composition have an effect on how quickly the glass corrodes. Glasses containing a high proportion of alkali or
alkaline earth The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are al ...
elements are more susceptible to corrosion than other glass compositions. The density of glass varies with chemical composition with values ranging from for
fused silica Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non- crystalline) form. This differs from all other commercial glasses in which other ingredients are added which ch ...
to for dense flint glass. Glass is stronger than most metals, with a theoretical
tensile strength Ultimate tensile strength (UTS), often shortened to tensile strength (TS), ultimate strength, or F_\text within equations, is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials t ...
for pure, flawless glass estimated at to due to its ability to undergo reversible compression without fracture. However, the presence of scratches, bubbles, and other microscopic flaws lead to a typical range of to in most commercial glasses. Several processes such as
toughening In materials science, toughening refers to the process of making a material more resistant to the propagation of cracks. When a crack propagates, the associated irreversible work in different materials classes is different. Thus, the most effectiv ...
can increase the strength of glass. Carefully drawn flawless glass fibres can be produced with strength of up to .


Reputed flow

The observation that old windows are sometimes found to be thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a timescale of centuries, the assumption being that the glass has exhibited the liquid property of flowing from one shape to another. This assumption is incorrect, as once solidified, glass stops flowing. The sags and ripples observed in old glass were already there the day it was made; manufacturing processes used in the past produced sheets with imperfect surfaces and non-uniform thickness. (The near-perfect float glass used today only became widespread in the 1960s.) The rate of glass flow in mediaeval windows was calculated in 2017. It was found that the glass was 16 orders of magnitude (1016 times) less viscous (hence freer-flowing) than expected at room temperature—16 orders of magnitude less than previous estimates based on soda–lime–silicate glass. It was estimated that the rate of flow would not exceed 1 nm per billion years.


Types


Silicate

Silicon dioxide Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
(SiO2) is a common fundamental constituent of glass.
Fused quartz Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO2) in amorphous (non-crystalline) form. This differs from all other commercial glasses in which other ingredients are added which change ...
is a glass made from chemically-pure silica. It has very low thermal expansion and excellent resistance to
thermal shock Thermal shock is a type of rapidly transient mechanical load. By definition, it is a mechanical load caused by a rapid change of temperature of a certain point. It can be also extended to the case of a thermal gradient, which makes different pa ...
, being able to survive immersion in water while red hot, resists high temperatures (1000–1500 °C) and chemical weathering, and is very hard. It is also transparent to a wider spectral range than ordinary glass, extending from the visible further into both the UV and IR ranges, and is sometimes used where transparency to these wavelengths is necessary. Fused quartz is used for high-temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc. However, its high melting temperature (1723 °C) and viscosity make it difficult to work with. Therefore, normally, other substances (fluxes) are added to lower the melting temperature and simplify glass processing.


Soda–lime

Sodium carbonate (Na2CO3, "soda") is a common additive and acts to lower the glass-transition temperature. However, sodium silicate is
water-soluble In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solub ...
, so
lime Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...
(CaO,
calcium oxide Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term "''lime''" connotes calcium-containing inorganic ...
, generally obtained from
limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
), along with
magnesium oxide Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...
(MgO), and aluminium oxide (Al2O3), are commonly added to improve chemical durability. Soda–lime glasses (Na2O) + lime (CaO) + magnesia (MgO) + alumina (Al2O3) account for over 75% of manufactured glass, containing about 70 to 74% silica by weight.B.H.W.S. de Jong, "Glass"; in "Ullmann's Encyclopedia of Industrial Chemistry"; 5th edition, vol. A12, VCH Publishers, Weinheim, Germany, 1989, , pp. 365–432. Soda–lime–silicate glass is transparent, easily formed, and most suitable for window glass and tableware. However, it has a high thermal expansion and poor resistance to heat. Soda–lime glass is typically used for
window A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent mat ...
s,
bottle A bottle is a narrow-necked container made of an impermeable material (such as glass, plastic or aluminium) in various shapes and sizes that stores and transports liquids. Its mouth, at the bottling line, can be sealed with an internal stop ...
s, light bulbs, and
jar A jar is a rigid, cylindrical or slightly conical container, typically made of glass, ceramic, or plastic, with a wide mouth or opening that can be closed with a lid, screw cap, lug cap, cork stopper, roll-on cap, crimp-on cap, press-on c ...
s.


Borosilicate

Borosilicate glass Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10−6 K−1 at 20 °C), m ...
es (e.g.
Pyrex Pyrex (trademarked as ''PYREX'' and ''pyrex'') is a brand introduced by Corning Inc. in 1915 for a line of clear, low-thermal-expansion borosilicate glass used for laboratory glassware and kitchenware. It was later expanded to include kitchenwa ...
, Duran) typically contain 5–13%
boron trioxide Boron trioxide or diboron trioxide is the oxide of boron with the formula . It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized only with great difficulty. It is also called boric oxide or boria. It h ...
(B2O3). Borosilicate glasses have fairly low coefficients of thermal expansion (7740 Pyrex CTE is 3.25/°C as compared to about 9/°C for a typical soda–lime glass). They are, therefore, less subject to
stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
caused by
thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...
and thus less vulnerable to cracking from
thermal shock Thermal shock is a type of rapidly transient mechanical load. By definition, it is a mechanical load caused by a rapid change of temperature of a certain point. It can be also extended to the case of a thermal gradient, which makes different pa ...
. They are commonly used for e.g. labware, household cookware, and sealed beam car
head lamp A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, ''headlamp'' is the term for the device itself and ''headlight'' is the term for ...
s.


Lead

The addition of
lead(II) oxide Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula Pb O. PbO occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern ap ...
into silicate glass lowers melting point and
viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...
of the melt. The high density of
lead glass Lead glass, commonly called crystal, is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead glass contains typically 18–40% (by weight) lead(II) oxide (PbO), while modern lead crystal, historically al ...
(silica + lead oxide (PbO) + potassium oxide (K2O) + soda (Na2O) + zinc oxide (ZnO) + alumina) results in a high electron density, and hence high refractive index, making the look of glassware more brilliant and causing noticeably more
specular reflection Specular reflection, or regular reflection, is the mirror-like reflection of waves, such as light, from a surface. The law of reflection states that a reflected ray of light emerges from the reflecting surface at the same angle to the surf ...
and increased
optical dispersion In optics, and by analogy other branches of physics dealing with wave propagation, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency; sometimes the term chromatic dispersion is used for specificity to o ...
. Lead glass has a high elasticity, making the glassware more workable and giving rise to a clear "ring" sound when struck. However, lead glass cannot withstand high temperatures well. Lead oxide also facilitates solubility of other metal oxides and is used in colored glass. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glass); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in
vitreous enamel Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate by firing, usually between . The powder melts, flows, and then hardens to a smooth, durable vitreous coating. The word comes from the Lati ...
s and
glass solder Glass frit bonding, also referred to as glass soldering or seal glass bonding, describes a wafer bonding technique with an intermediate glass layer. It is a widely used encapsulation technology for surface micro-machined structures, e.g., accele ...
s. The high
ionic radius Ionic radius, ''r''ion, is the radius of a monatomic ion in an ionic crystal structure. Although neither atoms nor ions have sharp boundaries, they are treated as if they were hard spheres with radii such that the sum of ionic radii of the catio ...
of the Pb2+ ion renders it highly immobile and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda–lime glass (108.5 vs 106.5 Ω⋅cm, DC at 250 °C).


Aluminosilicate

Aluminosilicate glass typically contains 5–10% alumina (Al2O3). Aluminosilicate glass tends to be more difficult to melt and shape compared to borosilicate compositions, but has excellent thermal resistance and durability. Aluminosilicate glass is extensively used for
fiberglass Fiberglass (American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...
, used for making glass-reinforced plastics (boats, fishing rods, etc.), top-of-stove cookware, and halogen bulb glass.


Other oxide additives

The addition of barium also increases the refractive index.
Thorium oxide Thorium dioxide (ThO2), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in colour. Also known as thoria, it is produced mainly as a by-product of lanthanide and uranium production. Thorianite is the name of the minera ...
gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by
lanthanum oxide Lanthanum(III) oxide, also known as lanthana, chemical formula , is an inorganic compound containing the rare earth element lanthanum and oxygen. It is used in some ferroelectric materials, as a component of optical materials, and is a feedstock ...
in modern eyeglasses. Iron can be incorporated into glass to absorb
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
radiation, for example in heat-absorbing filters for movie projectors, while
cerium(IV) oxide Cerium(IV) oxide, also known as ceric oxide, ceric dioxide, ceria, cerium oxide or cerium dioxide, is an oxide of the rare-earth metal cerium. It is a pale yellow-white powder with the chemical formula CeO2. It is an important commercial produc ...
can be used for glass that absorbs
ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
wavelengths. Fluorine lowers the dielectric constant of glass. Fluorine is highly
electronegative Electronegativity, symbolized as , is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the d ...
and lowers the polarizability of the material. Fluoride silicate glasses are used in manufacture of integrated circuits as an insulator.


Glass-ceramics

Glass-ceramic Glass-ceramics are polycrystalline materials produced through controlled crystallization of base glass, producing a fine uniform dispersion of crystals throughout the bulk material. Crystallization is accomplished by subjecting suitable glasses to ...
materials contain both non-crystalline glass and
crystalline A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
phases. They are formed by controlled nucleation and partial crystallisation of a base glass by heat treatment. Crystalline grains are often embedded within a non-crystalline intergranular phase of
grain boundaries In materials science, a grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are two-dimensional defects in the crystal structure, and tend to decrease the electrical and thermal ...
. Glass-ceramics exhibit advantageous thermal, chemical, biological, and dielectric properties as compared to metals or organic polymers. The most commercially important property of glass-ceramics is their imperviousness to thermal shock. Thus, glass-ceramics have become extremely useful for countertop cooking and industrial processes. The negative
thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...
coefficient (CTE) of the crystalline ceramic phase can be balanced with the positive CTE of the glassy phase. At a certain point (~70% crystalline) the glass-ceramic has a net CTE near zero. This type of
glass-ceramic Glass-ceramics are polycrystalline materials produced through controlled crystallization of base glass, producing a fine uniform dispersion of crystals throughout the bulk material. Crystallization is accomplished by subjecting suitable glasses to ...
exhibits excellent mechanical properties and can sustain repeated and quick temperature changes up to 1000 °C.


Fibreglass

Fibreglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...
(also called glass fibre reinforced plastic, GRP) is a
composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
made by reinforcing a plastic
resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on n ...
with glass fibres. It is made by melting glass and stretching the glass into fibres. These fibres are woven together into a cloth and left to set in a plastic resin. Fibreglass has the properties of being lightweight and corrosion resistant, and is a good insulator enabling its use as building insulation material and for electronic housing for consumer products. Fibreglass was originally used in the United Kingdom and United States during
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
to manufacture
radome A radome (a portmanteau of radar and dome) is a structural, weatherproof enclosure that protects a radar antenna. The radome is constructed of material transparent to radio waves. Radomes protect the antenna from weather and conceal antenna e ...
s. Uses of fibreglass include building and construction materials, boat hulls, car body parts, and aerospace composite materials. Glass-fibre wool is an excellent
thermal A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...
and
sound In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' b ...
insulation material, commonly used in buildings (e.g. attic and
cavity wall insulation A cavity wall is a type of wall that has a hollow center. They can be described as consisting of two "skins" separated by a hollow space (cavity). The skins typically are masonry, such as brick or cinder block. Masonry is an absorbent material ...
), and plumbing (e.g.
pipe insulation Pipe Insulation is thermal or acoustic insulation used on pipework. Applications Condensation control Where pipes operate at below-ambient temperatures, the potential exists for water vapour to condense on the pipe surface. Moisture is known to ...
), and
soundproofing Soundproofing is any means of impeding sound propagation. There are several basic approaches to reducing sound: increasing the distance between source and receiver, decoupling, using noise barriers to reflect or absorb the energy of the sound ...
. It is produced by forcing molten glass through a fine mesh by centripetal force, and breaking the extruded glass fibres into short lengths using a stream of high-velocity air. The fibres are bonded with an adhesive spray and the resulting wool mat is cut and packed in rolls or panels.


Non-silicate

Besides common silica-based glasses many other
inorganic In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemist ...
and organic materials may also form glasses, including
metals A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typical ...
,
aluminate In chemistry, an aluminate is a compound containing an oxyanion of aluminium, such as sodium aluminate. In the naming of inorganic compounds, it is a suffix that indicates a polyatomic anion with a central aluminum atom. Aluminate oxyanions Alum ...
s,
phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...
s,
borate A borate is any of several boron oxyanions, negative ions consisting of boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt with such anions, such as sodium metaborate, and disodium tetraborate . The name also re ...
s,
chalcogenides : 220px, Cadmium sulfide, a prototypical metal chalcogenide, is used as a yellow pigment. A chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. Although all group 16 elements ...
, fluorides, germanates (glasses based on GeO2), tellurites (glasses based on TeO2), antimonates (glasses based on Sb2O3), arsenates (glasses based on As2O3), titanates (glasses based on TiO2), tantalates (glasses based on Ta2O5), nitrates,
carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...
s, plastics,
acrylic Acrylic may refer to: Chemicals and materials * Acrylic acid, the simplest acrylic compound * Acrylate polymer, a group of polymers (plastics) noted for transparency and elasticity * Acrylic resin, a group of related thermoplastic or thermosett ...
, and many other substances. Some of these glasses (e.g.
Germanium dioxide Germanium dioxide, also called germanium(IV) oxide, germania, and salt of germanium, is an inorganic compound with the chemical formula Ge O2. It is the main commercial source of germanium. It also forms as a passivation layer on pure germaniu ...
(GeO2, Germania), in many respects a structural analogue of silica, fluoride,
aluminate In chemistry, an aluminate is a compound containing an oxyanion of aluminium, such as sodium aluminate. In the naming of inorganic compounds, it is a suffix that indicates a polyatomic anion with a central aluminum atom. Aluminate oxyanions Alum ...
,
phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...
,
borate A borate is any of several boron oxyanions, negative ions consisting of boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt with such anions, such as sodium metaborate, and disodium tetraborate . The name also re ...
, and
chalcogenide : 220px, Cadmium sulfide, a prototypical metal chalcogenide, is used as a yellow pigment. A chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. Although all group 16 elements ...
glasses) have physico-chemical properties useful for their application in
fibre-optic An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means t ...
waveguide A waveguide is a structure that guides waves, such as electromagnetic waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Without the physical constraint of a waveguide, wave intensities de ...
s in communication networks and other specialized technological applications. Silica-free glasses may often have poor glass forming tendencies. Novel techniques, including containerless processing by
aerodynamic levitation Aerodynamic levitation is the use of gas pressure to levitate materials so that they are no longer in physical contact with any container. In scientific experiments this removes contamination and nucleation issues associated with physical contac ...
(cooling the melt whilst it floats on a gas stream) or
splat quenching Splat quenching is a metallurgical, metal morphing technique used for forming metals with a particular crystal structure by means of extremely rapid quenching, or cooling. A typical technique for splat quenching involves casting molten metal by pou ...
(pressing the melt between two metal anvils or rollers), may be used increase cooling rate, or reduce crystal nucleation triggers.


Amorphous metals

In the past, small batches of
amorphous metal An amorphous metal (also known as metallic glass, glassy metal, or shiny metal) is a solid metallic material, usually an alloy, with disordered atomic-scale structure. Most metals are crystalline in their solid state, which means they have a high ...
s with high surface area configurations (ribbons, wires, films, etc.) have been produced through the implementation of extremely rapid rates of cooling. Amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk. A number of alloys have been produced in layers with thickness exceeding 1 millimeter. These are known as bulk metallic glasses (BMG). Liquidmetal Technologies sell a number of
zirconium Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'' ...
-based BMGs. Batches of amorphous steel have also been produced that demonstrate mechanical properties far exceeding those found in conventional steel alloys. Experimental evidence indicates that the system Al-Fe-Si may undergo a ''first-order transition'' to an amorphous form (dubbed "q-glass") on rapid cooling from the melt.
Transmission electron microscopy Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a g ...
(TEM) images indicate that q-glass nucleates from the melt as discrete particles with a uniform spherical growth in all directions. While x-ray diffraction reveals the isotropic nature of q-glass, a nucleation barrier exists implying an interfacial discontinuity (or internal surface) between the glass and melt phases.


Polymers

Important polymer glasses include amorphous and glassy pharmaceutical compounds. These are useful because the solubility of the compound is greatly increased when it is amorphous compared to the same crystalline composition. Many emerging pharmaceuticals are practically insoluble in their crystalline forms. Many polymer
thermoplastic A thermoplastic, or thermosoft plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular weight. The polymer chains associate ...
s familiar from everyday use are glasses. For many applications, like
glass bottles A glass bottle is a bottle made from glass. Glass bottles can vary in size considerably, but are most commonly found in sizes ranging between about 200 millilitres and 1.5 litres. Common uses for glass bottles include food condiments, soda, liq ...
or eyewear, polymer glasses (
acrylic glass Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acrylite ...
, polycarbonate or polyethylene terephthalate) are a lighter alternative to traditional glass.


Molecular liquids and molten salts

Molecular liquids, electrolytes,
molten salt Molten salt is salt which is solid at standard temperature and pressure but enters the liquid phase due to elevated temperature. Regular table salt has a melting point of 801 °C (1474°F) and a heat of fusion of 520 J/g.Journal of Chemical T ...
s, and aqueous solutions are mixtures of different molecules or
ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
s that do not form a covalent network but interact only through weak
van der Waals force In molecular physics, the van der Waals force is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and th ...
s or through transient hydrogen bonds. In a mixture of three or more ionic species of dissimilar size and shape, crystallization can be so difficult that the liquid can easily be supercooled into a glass. Examples include LiCl:''R''H2O (a solution of
lithium chloride Lithium chloride is a chemical compound with the formula Li Cl. The salt is a typical ionic compound (with certain covalent characteristics), although the small size of the Li+ ion gives rise to properties not seen for other alkali metal chlorid ...
salt and water molecules) in the composition range 4<''R''<8. sugar glass, or Ca0.4K0.6(NO3)1.4. Glass electrolytes in the form of Ba-doped Li-glass and Ba-doped Na-glass have been proposed as solutions to problems identified with organic liquid electrolytes used in modern lithium-ion battery cells.


Production

Following the
glass batch Glass batch calculation or glass batching is used to determine the correct mix of raw materials (batch) for a glass melt. Principle The raw materials mixture for glass melting is termed "batch". The batch must be measured properly to achieve a giv ...
preparation and mixing, the raw materials are transported to the furnace.
Soda–lime glass Soda–lime glass, also called soda–lime–silica glass, is the most prevalent type of glass, used for windowpanes and glass containers (bottles and jars) for beverages, food, and some commodity items. Some glass bakeware is made of soda-lime ...
for mass production is melted in glass melting furnaces. Smaller scale furnaces for specialty glasses include electric melters, pot furnaces, and day tanks. After melting, homogenization and refining (removal of bubbles), the glass is formed.
Flat glass Plate glass, flat glass or sheet glass is a type of glass, initially produced in plane form, commonly used for windows, glass doors, transparent walls, and windscreens. For modern architectural and automotive applications, the flat glass is ...
for windows and similar applications is formed by the float glass process, developed between 1953 and 1957 by Sir
Alastair Pilkington Sir Lionel Alexander Bethune Pilkington (7 January 1920 – 5 May 1995), known as Sir Alastair Pilkington, was a British engineer and businessman who invented and perfected the float glass process for commercial manufacturing of plate glass. E ...
and Kenneth Bickerstaff of the UK's Pilkington Brothers, who created a continuous ribbon of glass using a molten tin bath on which the molten glass flows unhindered under the influence of gravity. The top surface of the glass is subjected to nitrogen under pressure to obtain a polished finish.
Container glass Container glass is a type of glass for the production of glass containers, such as bottles, jars, drinkware, and bowls. Container glass stands in contrast to ''flat glass'' (used for windows, glass doors, transparent walls, windshields) and ''gl ...
for common bottles and jars is formed by blowing and pressing methods. This glass is often slightly modified chemically (with more alumina and calcium oxide) for greater water resistance. Once the desired form is obtained, glass is usually annealed for the removal of stresses and to increase the glass's hardness and durability. Surface treatments, coatings or
lamination Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materia ...
may follow to improve the chemical durability ( glass container coatings, glass container internal treatment), strength (
toughened glass Tempered or toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the interior into tens ...
,
bulletproof glass Bulletproof glass, ballistic glass, transparent armor, or bullet-resistant glass is a strong and optically transparent material that is particularly resistant to penetration by projectiles. Like any other material, it is not completely impenetr ...
,
windshield The windshield (North American English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike, truck, train, boat or streetcar is the front window, which provides visibility while protecting occupants from the elements. ...
s), or optical properties (
insulated glazing Insulating glass (IG) consists of two or more glass window panes separated by a space to reduce heat transfer across a part of the building envelope. A window with insulating glass is commonly known as double glazing or a double-paned window, ...
, anti-reflective coating). New chemical glass compositions or new treatment techniques can be initially investigated in small-scale laboratory experiments. The raw materials for laboratory-scale glass melts are often different from those used in mass production because the cost factor has a low priority. In the laboratory mostly pure
chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...
s are used. Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment (such as alkali or
alkaline earth metal The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are all ...
oxides and hydroxides, or
boron oxide Boron oxide may refer to one of several oxides of boron: *Boron trioxide Boron trioxide or diboron trioxide is the oxide of boron with the formula . It is a colorless transparent solid, almost always glassy (amorphous), which can be crystallized ...
), or that the impurities are quantified (loss on ignition). Evaporation losses during glass melting should be considered during the selection of the raw materials, e.g.,
sodium selenite Sodium selenite is the inorganic compound with the formula Na2SeO3. This salt is a colourless solid. The pentahydrate Na2SeO3(H2O)5 is the most common water-soluble selenium compound. Synthesis and fundamental reactions Sodium selenite usually i ...
may be preferred over easily evaporating
selenium dioxide Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium. Properties Solid SeO2 is a one-dimensional polymer, the chain consisting of alternating seleniu ...
(SeO2). Also, more readily reacting raw materials may be preferred over relatively inert ones, such as
aluminum hydroxide Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic an ...
(Al(OH)3) over alumina (Al2O3). Usually, the melts are carried out in platinum crucibles to reduce contamination from the crucible material. Glass
homogeneity Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the Uniformity (chemistry), uniformity of a Chemical substance, substance or organism. A material or image that is homogeneous is uniform in compos ...
is achieved by homogenizing the raw materials mixture (
glass batch Glass batch calculation or glass batching is used to determine the correct mix of raw materials (batch) for a glass melt. Principle The raw materials mixture for glass melting is termed "batch". The batch must be measured properly to achieve a giv ...
), by stirring the melt, and by crushing and re-melting the first melt. The obtained glass is usually annealed to prevent breakage during processing.


Colour

Colour in glass may be obtained by addition of homogenously distributed electrically charged ions (or colour centres). While ordinary
soda–lime glass Soda–lime glass, also called soda–lime–silica glass, is the most prevalent type of glass, used for windowpanes and glass containers (bottles and jars) for beverages, food, and some commodity items. Some glass bakeware is made of soda-lime ...
appears colourless in thin section,
iron(II) oxide Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists ...
(FeO) impurities produce a green tint in thick sections. Manganese dioxide (MnO2), which gives glass a purple colour, may be added to remove the green tint given by FeO. FeO and
chromium(III) oxide Chromium(III) oxide (or chromia) is an inorganic compound with the formula . It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite. Structure and properties has the corundum ...
(Cr2O3) additives are used in the production of green bottles.
Iron (III) oxide Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally a ...
, on the other-hand, produces yellow or yellow-brown glass. Low concentrations (0.025 to 0.1%) of
cobalt oxide Cobalt oxide is a family of chemical compounds consisting of cobalt and oxygen atoms. Compounds in the cobalt oxide family include: * Cobalt(II) oxide (cobaltous oxide), CoO *Cobalt(III) oxide Cobalt(III) oxide is the inorganic compound with the ...
(CoO) produces rich, deep blue
cobalt glass Cobalt glass—known as "smalt" when ground as a pigment—is a deep blue coloured glass prepared by including a cobalt compound, typically cobalt oxide or cobalt carbonate, in a glass melt. Cobalt is a very intense colouring agent and very litt ...
. Chromium is a very powerful colourising agent, yielding dark green. Sulphur combined with
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
and iron salts produces amber glass ranging from yellowish to almost black. A glass melt can also acquire an amber colour from a reducing combustion atmosphere.
Cadmium sulfide Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare mi ...
produces imperial
red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondar ...
, and combined with selenium can produce shades of yellow, orange, and red. The additive
Copper(II) oxide Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite. It is ...
(CuO) produces a
turquoise Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula . It is rare and valuable in finer grades and has been prized as a gemstone and ornamental stone for thousands of year ...
colour in glass, in contrast to
Copper(I) oxide Copper(I) oxide or cuprous oxide is the inorganic compound with the formula Cu2O. It is one of the principal oxides of copper, the other being or copper(II) oxide or cupric oxide (CuO). This red-coloured solid is a component of some antifoulin ...
(Cu2O) which gives a dull brown-red colour. File:Bottle, wine (AM 1997.80.28-1).jpg, alt=A green glass bottle,
Iron(II) oxide Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists ...
and
chromium(III) oxide Chromium(III) oxide (or chromia) is an inorganic compound with the formula . It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite. Structure and properties has the corundum ...
additives are often used in the production of green bottles. File:Bristol.blue.glass.arp.750pix.jpg, alt=Several examples of deep blue glass,
Cobalt oxide Cobalt oxide is a family of chemical compounds consisting of cobalt and oxygen atoms. Compounds in the cobalt oxide family include: * Cobalt(II) oxide (cobaltous oxide), CoO *Cobalt(III) oxide Cobalt(III) oxide is the inorganic compound with the ...
produces rich, deep blue glass, such as
Bristol blue glass Bristol blue glass has been made in Bristol, England, since the 18th century, with a break between the 1920s and 1980s. History During the late 18th century Richard Champion, a Bristol merchant and potter, making Bristol porcelain, was workin ...
. File:Colour Eclipse, Danny Lane.jpg, alt=Three glass disks, with one colored turquoise, another purple, and a third colored red, Different oxide additives produce the different colours in glass:
turquoise Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula . It is rare and valuable in finer grades and has been prized as a gemstone and ornamental stone for thousands of year ...
(
Copper(II) oxide Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black solid, it is one of the two stable oxides of copper, the other being Cu2O or copper(I) oxide (cuprous oxide). As a mineral, it is known as tenorite. It is ...
), purple ( Manganese dioxide), and red (
Cadmium sulfide Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare mi ...
). File:Chinese snuff bottle, Qing dynasty, glass bottle with amber stopper, Honolulu Museum of Art.JPG, Red glass bottle with yellow glass overlay File:Glass ornaments.JPG, Amber-coloured glass File:Glass garland bowl MET DP122006.jpg, Four-colour Roman glass bowl, manufactured circa 1st century B.C.


Uses


Architecture and windows

Soda–lime sheet glass is typically used as transparent glazing material, typically as
window A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent mat ...
s in external walls of buildings. Float or rolled sheet glass products is cut to size either by
scoring Score or scorer may refer to: *Test score, the result of an exam or test Business * Score Digital, now part of Bauer Radio * Score Entertainment, a former American trading card design and manufacturing company * Score Media, a former Canadian m ...
and snapping the material, laser cutting, water jets, or
diamond blade A diamond blade is a saw blade which has diamonds fixed on its edge for cutting hard or abrasive materials. There are many types of diamond blade, and they have many uses, including cutting stone, concrete, asphalt, bricks, coal balls, glass, an ...
d saw. The glass may be thermally or chemically tempered (strengthened) for
safety Safety is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk. Meanings There are two slightly dif ...
and bent or curved during heating. Surface coatings may be added for specific functions such as scratch resistance, blocking specific wavelengths of light (e.g.
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
or
ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
), dirt-repellence (e.g. self-cleaning glass), or switchable
electrochromic Electrochromism is a phenomenon in which a material displays changes in color or opacity in response to an electrical stimulus. In this way, a smart window made of an electrochromic material can block specific wavelengths of ultraviolet, vis ...
coatings. Structural glazing systems represent one of the most significant architectural innovations of modern times, where glass buildings now often dominate
skyline A skyline is the outline or shape viewed near the horizon. It can be created by a city’s overall structure, or by human intervention in a rural setting, or in nature that is formed where the sky meets buildings or the land. City skyline ...
s of many modern
cities A city is a human settlement of notable size.Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. London: Routledge. It can be def ...
. These systems use stainless steel fittings countersunk into recesses in the corners of the glass panels allowing strengthened panes to appear unsupported creating a flush exterior. Structural glazing systems have their roots in iron and glass conservatories of the nineteenth century


Tableware

Glass is an essential component of tableware and is typically used for water,
beer Beer is one of the oldest and the most widely consumed type of alcoholic drink in the world, and the third most popular drink overall after water and tea. It is produced by the brewing and fermentation of starches, mainly derived from ce ...
and
wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...
drinking glasses. Wine glasses are typically
stemware Stemware is drinkware that stands on stems above a base. It is usually made from glass, but may be made from ceramics or metals. The stem allows the drinker to hold the glass without affecting the temperature of the drink. Stemware includes: * ...
, i.e. goblets formed from a bowl, stem, and foot. Crystal or
Lead crystal Lead glass, commonly called crystal, is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead glass contains typically 18–40% (by weight) lead(II) oxide (PbO), while modern lead crystal, historically als ...
glass may be cut and polished to produce decorative drinking glasses with gleaming facets. Other uses of glass in tableware include
decanters A decanter is a vessel that is used to hold the decantation of a liquid (such as wine) which may contain sediment. Decanters, which have a varied shape and design, have been traditionally made from glass or crystal. Their volume is usually equ ...
,
jug A jug is a type of container commonly used to hold liquids. It has an opening, sometimes narrow, from which to pour or drink, and has a handle, and often a pouring lip. Jugs throughout history have been made of metal, and ceramic, or glass, and ...
s, plates, and
bowl A bowl is a typically round dish or container generally used for preparing, serving, or consuming food. The interior of a bowl is characteristically shaped like a spherical cap, with the edges and the bottom forming a seamless curve. This makes ...
s. File:Jubilee Campus MMB «62 Melton Hall Christmas Dinner.jpg, Wine glasses and other glass tableware File:British dimpled glass pint jug with ale.jpg, Dimpled glass beer pint jug File:Crystal glass.jpg, Cut lead crystal glass File:Decanter and Stopper LACMA 56.35.29a-b.jpg, A glass
decanter A decanter is a vessel that is used to hold the decantation of a liquid (such as wine) which may contain sediment. Decanters, which have a varied shape and design, have been traditionally made from glass or crystal. Their volume is usually equ ...
and stopper


Packaging

The inert and impermeable nature of glass makes it a stable and widely used material for food and drink packaging as
glass bottle A glass bottle is a bottle made from glass. Glass bottles can vary in size considerably, but are most commonly found in sizes ranging between about 200 millilitres and 1.5 litres. Common uses for glass bottles include food condiments, soda, liq ...
s and
jar A jar is a rigid, cylindrical or slightly conical container, typically made of glass, ceramic, or plastic, with a wide mouth or opening that can be closed with a lid, screw cap, lug cap, cork stopper, roll-on cap, crimp-on cap, press-on c ...
s. Most
container glass Container glass is a type of glass for the production of glass containers, such as bottles, jars, drinkware, and bowls. Container glass stands in contrast to ''flat glass'' (used for windows, glass doors, transparent walls, windshields) and ''gl ...
is
soda–lime glass Soda–lime glass, also called soda–lime–silica glass, is the most prevalent type of glass, used for windowpanes and glass containers (bottles and jars) for beverages, food, and some commodity items. Some glass bakeware is made of soda-lime ...
, produced by blowing and pressing techniques. Container glass has a lower
magnesium oxide Magnesium oxide ( Mg O), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of MgO and consists of a lattice of Mg2+ ions and O2− ions ...
and
sodium oxide Sodium oxide is a chemical compound with the formula Na2 O. It is used in ceramics and glasses. It is a white solid but the compound is rarely encountered. Instead "sodium oxide" is used to describe components of various materials such as glass ...
content than flat glass, and a higher
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...
,
calcium oxide Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound. It is a white, caustic, alkaline, crystalline solid at room temperature. The broadly used term "''lime''" connotes calcium-containing inorganic ...
, and aluminum oxide content."High temperature glass melt property database for process modeling"; Eds.: Thomas P. Seward III and Terese Vascott; The American Ceramic Society, Westerville, Ohio, 2005, Its higher content of water-insoluble oxides imparts slightly higher
chemical durability Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
against water, which is advantageous for storing beverages and food. Glass packaging is sustainable, readily recycled, reusable and refillable. For electronics applications, glass can be used as a substrate in the manufacture of
integrated passive devices Integrated passive devices (IPDs), also known as integrated passive components (IPCs) or embedded passive components (EPC), are electronic components where resistors (R), capacitors (C), inductors (L)/coils/chokes, microstriplines, impedance matchi ...
, thin-film bulk acoustic resonators, and as a
hermetic seal A hermetic seal is any type of sealing that makes a given object airtight (preventing the passage of air, oxygen, or other gases). The term originally applied to airtight glass containers, but as technology advanced it applied to a larger categor ...
ing material in device packaging, including very thin solely glass based encapsulation of integrated circuits and other semiconductors in high manufacturing volumes.


Laboratories

Glass is an important material in scientific laboratories for the manufacture of experimental apparatus because it is relatively cheap, readily formed into required shapes for experiment, easy to keep clean, can withstand heat and cold treatment, is generally non-reactive with many reagents, and its transparency allows for the observation of chemical reactions and processes.
Laboratory glassware Laboratory glassware refers to a variety of equipment used in scientific work, and traditionally made of glass. Glass can be blown, bent, cut, molded, and formed into many sizes and shapes, and is therefore common in chemistry, biology, and anal ...
applications include flasks, petri dishes,
test tube A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom. Test tubes are usually placed in ...
s, pipettes,
graduated cylinder A graduated cylinder, also known as a measuring cylinder or mixing cylinder, is a common piece of laboratory equipment used to measure the volume of a liquid. It has a narrow cylindrical shape. Each marked line on the graduated cylinder represent ...
s, glass lined metallic containers for chemical processing,
fractionation column A fractionating column or fractional column is an essential item used in the distillation of liquid mixtures to separate the mixture into its component parts, or fractions, based on the differences in volatilities. Fractionating columns are used in ...
s, glass pipes, Schlenk lines, gauges, and
thermometer A thermometer is a device that measures temperature or a temperature gradient (the degree of hotness or coldness of an object). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer ...
s. Although most standard laboratory glassware has been mass-produced since the 1920s, scientists still employ skilled
glassblower Glassblowing is a glassforming technique that involves inflating molten glass into a bubble (or parison) with the aid of a blowpipe (or blow tube). A person who blows glass is called a ''glassblower'', ''glassmith'', or ''gaffer''. A '' lampworke ...
s to manufacture bespoke glass apparatus for their experimental requirements. File:Vigreux column lab.jpg, A Vigreux column in a laboratory setup File:Double vac line front view.jpg, A Schlenk line with four ports File:Different types of graduated cylinder- 10ml, 25ml, 50ml and 100 ml graduated cylinder.jpg,
Graduated cylinder A graduated cylinder, also known as a measuring cylinder or mixing cylinder, is a common piece of laboratory equipment used to measure the volume of a liquid. It has a narrow cylindrical shape. Each marked line on the graduated cylinder represent ...
s File:250 mL Erlenmeyer flask.jpg, Erlenmeyer
flask Flask may refer to: Container * Hip flask, a small container used to carry a small amount of liquid * Laboratory flask, laboratory glassware for holding larger volumes than simple test tubes ** Erlenmeyer flask, a common laboratory flask wit ...


Optics

Glass is a ubiquitous material in
optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultrav ...
by virtue of its ability to
refract In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomeno ...
, reflect, and
transmit Transmit is a file transfer client program for macOS. Developed by Panic, Transmit is shareware. After a seven-day trial period, the product can only be used for seven-minute sessions until it has been purchased. Originally built as an FTP client ...
light. These and other optical properties can be controlled by varying chemical compositions, thermal treatment, and manufacturing techniques. The many applications of glass in optics includes
glasses Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples ...
for eyesight correction, imaging optics (e.g.
lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements ...
es and
mirror A mirror or looking glass is an object that reflects an image. Light that bounces off a mirror will show an image of whatever is in front of it, when focused through the lens of the eye or a camera. Mirrors reverse the direction of the im ...
s in
telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observ ...
s,
microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisi ...
s, and
camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...
s),
fibre optics An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means t ...
in
telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
technology, and integrated optics.
Microlens A microlens is a small lens, generally with a diameter less than a millimetre (mm) and often as small as 10 micrometres (µm). The small sizes of the lenses means that a simple design can give good optical quality but sometimes unwanted effects ...
es and
gradient-index optics Gradient-index (GRIN) optics is the branch of optics covering optical effects produced by a gradient of the refractive index of a material. Such gradual variation can be used to produce lens (optics), lenses with flat surfaces, or lenses that do n ...
(where the
refractive index In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...
is non-uniform) find application in e.g. reading
optical disc In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...
s,
laser printer Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a negatively-charged cylinder called a "drum" to ...
s,
photocopier A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers ...
s, and
laser diode The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD, or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with e ...
s.


Art

Glass as art dates to least 1300 BC shown as an example of natural glass found in Tutankhamun's pectoral,Tut's gem hints at space impact
BBC News BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broad ...
, July 19, 2006.
which also contained
vitreous enamel Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate by firing, usually between . The powder melts, flows, and then hardens to a smooth, durable vitreous coating. The word comes from the Lati ...
, that is to say, melted coloured glass used on a metal backing.
Enamelled glass Enamelled glass or painted glass is glass which has been decorated with vitreous enamel (powdered glass, usually mixed with a binder) and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or o ...
, the decoration of glass vessels with coloured glass paints, has existed since 1300 BC, and was prominent in the early 20th century with
Art Nouveau glass Art Nouveau glass is fine glass in the Art Nouveau style. Typically the forms are undulating, sinuous and colorful art, usually inspired by natural forms. Pieces are generally larger than drinking glasses, and decorative rather than practical, oth ...
and that of the
House of Fabergé The House of Fabergé (; Russian: Дом Фаберже) was a jewellery firm founded in 1842 in Saint Petersburg, Russia, by Gustav Faberge, using the accented name ''Fabergé''. Gustav's sons – Peter Carl and Agathon – and grandsons follo ...
in St. Petersburg, Russia. Both techniques were used in stained glass, which reached its height roughly from 1000 to 1550, before a revival in the 19th century. The 19th century saw a revival in ancient glass-making techniques including
cameo glass Cameo glass is a luxury form of glass art produced by cameo glass engraving or etching and carving through fused layers of differently colored glass to produce designs, usually with white opaque glass figures and motifs on a dark-colored backgroun ...
, achieved for the first time since the Roman Empire, initially mostly for pieces in a neo-classical style. The Art Nouveau movement made great use of glass, with
René Lalique René Jules Lalique (6 April 1860 – 1 May 1945) was a French jeweller, medallist, and glass designer known for his creations of glass art, perfume bottles, vases, jewellery, chandeliers, clocks, and automobile hood ornaments. Life Lalique' ...
,
Émile Gallé Émile Gallé (8 May 1846 in Nancy – 23 September 1904 in Nancy) was a French artist and designer who worked in glass, and is considered to be one of the major innovators in the French Art Nouveau movement. He was noted for his designs of ...
, and Daum of Nancy in the first French wave of the movement, producing coloured vases and similar pieces, often in cameo glass or in lustre glass techniques.
Louis Comfort Tiffany Louis Comfort Tiffany (February 18, 1848 – January 17, 1933) was an American artist and designer who worked in the decorative arts and is best known for his work in stained glass. He is the American artist most associated with the Art NouveauL ...
in America specialized in stained glass, both secular and religious, in panels and his famous lamps. The early 20th-century saw the large-scale factory production of glass art by firms such as
Waterford "Waterford remains the untaken city" , mapsize = 220px , pushpin_map = Ireland#Europe , pushpin_map_caption = Location within Ireland##Location within Europe , pushpin_relief = 1 , coordinates ...
and
Lalique Lalique is a French glassmaker, founded by renowned glassmaker and jeweller René Lalique in 1888. Lalique is best known for producing glass art, including perfume bottles, vases, and hood ornaments during the early twentieth century. Following t ...
. Small studios may hand-produce glass artworks. Techniques for producing glass art include
blowing Blowing may refer to: *Air *Breath *Blowing by a whale, from blowhole (anatomy) Industrial processes *Blowing (glassmaking) * Blowing (textile finishing) * Dry blowing, method to extract gold particles from dry soil without the use of water *Melt b ...
, kiln-casting, fusing, slumping, pâte de verre, flame-working, hot-sculpting and cold-working. Cold work includes traditional stained glass work and other methods of shaping glass at room temperature. Objects made out of glass include vessels,
paperweights A paperweight is a small solid object heavy enough, when placed on top of papers, to keep them from blowing away in a breeze or from moving under the strokes of a painting brush (as with Chinese calligraphy). While any object, such as a stone, ...
,
marbles A marble is a small spherical object often made from glass, clay, steel, plastic, or agate. They vary in size, and most commonly are about in diameter. These toys can be used for a variety of games called ''marbles'', as well being placed in mar ...
,
bead A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under ...
s, sculptures and
installation art Installation art is an artistic genre of three-dimensional works that are often site-specific and designed to transform the perception of a space. Generally, the term is applied to interior spaces, whereas exterior interventions are often called ...
. Image:Portland Vase BM Gem4036 n5.jpg, The
Portland Vase The Portland Vase is a Roman cameo glass vase, which is dated to between AD 1 and AD 25, though low BC dates have some scholarly support. It is the best known piece of Roman cameo glass and has served as an inspiration to many glass and porcelain ...
, Roman
cameo glass Cameo glass is a luxury form of glass art produced by cameo glass engraving or etching and carving through fused layers of differently colored glass to produce designs, usually with white opaque glass figures and motifs on a dark-colored backgroun ...
, about 5–25 AD File:Medallion St Demetrios Louvre OA6457.jpg, Byzantine cloisonné enamel plaque of St Demetrios, c. 1100, using the ''senkschmelz'' or "sunk" technique File:British Museum Royal Gold Cup.jpg, The
Royal Gold Cup The Royal Gold Cup or Saint Agnes Cup is a solid gold covered cup lavishly decorated with enamel and pearls. It was made for the French royal family at the end of the 14th century, and later belonged to several English monarchs before spending ...
with ''
basse-taille ''Basse-taille'' (bahss-tah-ee) is an enamelling technique in which the artist creates a low-relief pattern in metal, usually silver or gold, by engraving or chasing. The entire pattern is created in such a way that its highest point is lower ...
'' enamels on gold; weight 1.935 kg, late 14th-century.
Saint Agnes Agnes of Rome () is a virgin martyr, venerated as a saint in the Catholic Church, Oriental Orthodox Church and the Eastern Orthodox Church, as well as the Anglican Communion and Lutheran Churches. St. Agnes is one of several virgin martyrs co ...
appears to her friends in a vision. Image:Reichsadlerhumpen.jpg, The ''
Reichsadlerhumpen An Imperial Eagle beaker (german: Reichsadlerhumpen), or eagle glass, was a popular drinking vessel from the 16th until the late 18th century in the Holy Roman Empire. The enamelled glass was decorated with a double-headed eagle, usually in the s ...
'',
enamelled glass Enamelled glass or painted glass is glass which has been decorated with vitreous enamel (powdered glass, usually mixed with a binder) and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or o ...
with the double-headed eagle of the
Holy Roman Empire The Holy Roman Empire was a political entity in Western, Central, and Southern Europe that developed during the Early Middle Ages and continued until its dissolution in 1806 during the Napoleonic Wars. From the accession of Otto I in 962 ...
, and the arms of the various territories on its wings, was a popular showpiece of enamelled glass in the German lands from the 16th century on. File:Venetian Jar CMOG.jpg, alt=white jar with fine stripes, Filigree style
Venetian glass Venetian glass () is glassware made in Venice, typically on the island of Murano near the city. Traditionally it is made with a soda–lime "metal" and is typically elaborately decorated, with various "hot" glass-forming techniques, as well as ...
jar File:Gallé, nancy, vaso clematis, 1890-1900.JPG,
Émile Gallé Émile Gallé (8 May 1846 in Nancy – 23 September 1904 in Nancy) was a French artist and designer who worked in glass, and is considered to be one of the major innovators in the French Art Nouveau movement. He was noted for his designs of ...
, Marquetry glass vase with clematis flowers (1890-1900) File:Vase (Perruches) by René Jules Lalique, 1922, blown four mold glass - Cincinnati Art Museum - DSC04355.JPG, Glass vase by art nouveau artist
René Lalique René Jules Lalique (6 April 1860 – 1 May 1945) was a French jeweller, medallist, and glass designer known for his creations of glass art, perfume bottles, vases, jewellery, chandeliers, clocks, and automobile hood ornaments. Life Lalique' ...
File:Clara driscoll per tiffany studios, lampada laburnum, 1910 ca. 02.jpg, Clara Driscoll
Tiffany lamp Tiffany may refer to: People * Tiffany (given name), list of people with this name * Tiffany (surname), list of people with this surname Known mononymously as "Tiffany": * Tiffany Darwish, (born 1971), an American singer, songwriter, actress kn ...
,
laburnum ''Laburnum'', sometimes called golden chain or golden rain, is a genus of two species of small trees in the subfamily Faboideae of the pea family Fabaceae. The species are '' Laburnum anagyroides''—common laburnum and '' Laburnum alpinum'' ...
pattern, c. 1910 File:Glass.sculpture.kewgardens.london.arp.jpg, A glass sculpture by Dale Chihuly, "The Sun" at the "Gardens of Glass" exhibition in Kew Gardens, London File:Modern stained glass - geograph.org.uk - 921350.jpg, Modern stained glass window


See also

*
Fire glass Fire glass (also fire pit glass, fire rocks, fire beads or lava glass) is a type of tempered glass, chunks of which are used decoratively on fireplaces. Pieces of the glass are heaped around jets of burning gas, or around liquid ethanol, in order ...
* Flexible glass *
Kimberley points Kimberley points are a type of Aboriginal stone tool made by pressure flaking both discarded glass and stone. Best known for the points made of glass, these artifacts are an example of adaptive reuse of Western technology by a non-western culture ...
* Prince Rupert's drop *
Smart glass Smart glass or switchable glass (also called a smart window or switchable window) is a glass or glazing whose light transmission properties dynamically alter to control the passage of solar irradiation into buildings. In general, the glass chan ...


References


External links

*
The Story of Glass Making in Canada
from The Canadian Museum of Civilization.
"How Your Glass Ware Is Made"
by George W. Waltz, February 1951, '' Popular Science''.
All About Glass
from the Corning Museum of Glass: a collection of articles, multimedia, and virtual books all about glass, including th
Glass Dictionary

National Glass Association
The largest trade association representing the flat (architectural), auto glass, and window & door industries {{Authority control Amorphous solids Dielectrics Materials Packaging materials Sculpture materials Windows