Jasper, an
aggregate
Aggregate or aggregates may refer to:
Computing and mathematics
* collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...
of microgranular
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 form ...
and/or
cryptocrystalline
Cryptocrystalline is a rock microstructure, rock texture made up of such minute crystals that its crystalline nature is only vaguely revealed even microscopically in thin section by transmitted polarized light. Among the sedimentary rocks, chert a ...
chalcedony and other mineral phases,
[Kostov, R. I. 2010. Review on the mineralogical systematics of jasper and related rocks. – Archaeometry Workshop, 7, 3, 209-213]
PDF
/ref> is an 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 lingui ...
, impure variety of 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 one ...
, usually red, yellow, brown or green in color; and rarely blue. The common red color is due to iron(III)
In chemistry, iron(III) refers to the chemical element, element iron in its +3 oxidation number, oxidation state. In salt (chemistry), ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe3+.
The adjec ...
inclusions. Jasper breaks with a smooth surface and is used for ornamentation or as a gemstone
A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ...
. It can be highly polished and is used for items such as vases, seals
Seals may refer to:
* Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly:
** Earless seal, or "true seal"
** Fur seal
* Seal (emblem), a device to impress an emblem, used as a means of a ...
, and snuff boxes. The specific gravity
Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...
of jasper is typically 2.5 to 2.9. Jaspillite
Jaspillite, or ''jaspilite'' also '' itabirite'', is a chemical rock formed similar to chert, but is generally quite iron rich. It is also known as ''jasper taconite''. Jaspillite is typically a banded mixture of hematite and quartz common in the ...
is a banded-iron-formation rock that often has distinctive bands of jasper.
Etymology and history
The name means "spotted or speckled stone," and is derived via Old French
Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligib ...
''jaspre'' (variant of Anglo-Norman Anglo-Norman may refer to:
*Anglo-Normans, the medieval ruling class in England following the Norman conquest of 1066
*Anglo-Norman language
**Anglo-Norman literature
*Anglo-Norman England, or Norman England, the period in English history from 1066 ...
''jaspe'') and Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''iaspidem'' (nom. ''iaspis'') from Greek ἴασπις ''iaspis'' (feminine noun), from an Afroasiatic language
The Afroasiatic languages (or Afro-Asiatic), also known as Hamito-Semitic, or Semito-Hamitic, and sometimes also as Afrasian, Erythraean or Lisramic, are a language family of about 300 languages that are spoken predominantly in the geographic su ...
(cf. Hebrew
Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...
ישפה ''yashpeh'', Akkadian Akkadian or Accadian may refer to:
* Akkadians, inhabitants of the Akkadian Empire
* Akkadian language, an extinct Eastern Semitic language
* Akkadian literature, literature in this language
* Akkadian cuneiform
Cuneiform is a logo- syllabi ...
''yashupu''). This Semitic etymology is believed to be unrelated to that of the English given name Jasper
Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases,Kostov, R. I. 2010. Review on the mineralogical systematics of jasper and related rocks. – Archaeometry Workshop, 7, 3, 209-213PDF/ref> ...
, which is of Persian
Persian may refer to:
* People and things from Iran, historically called ''Persia'' in the English language
** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples
** Persian language, an Iranian language of the ...
origin, though the Persian word for the mineral jasper is also ''yashp'' ( یَشم).
Green jasper was used to make bow drill
A bow drill is a simple hand-operated type of tool, consisting of a rod (the ''spindle'' or ''drill shaft'') that is set in rapid rotary motion by means of a cord wrapped around it, kept taut by a bow which is pushed back and forth with one han ...
s in Mehrgarh
Mehrgarh (; ur, ) is a Neolithic archaeological site (dated ) situated on the Kacchi Plain of Balochistan in Pakistan. It is located near the Bolan Pass, to the west of the Indus River and between the modern-day Pakistani cities of Quetta, Ka ...
between 4th and 5th millennium BC. Jasper is known to have been a favorite gem in the ancient world; its name can be traced back in Arabic
Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
, Persian, Hebrew, Assyrian, Greek and Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
. On Minoan
The Minoan civilization was a Bronze Age Aegean civilization on the island of Crete and other Aegean Islands, whose earliest beginnings were from 3500BC, with the complex urban civilization beginning around 2000BC, and then declining from 1450B ...
Crete
Crete ( el, Κρήτη, translit=, Modern: , Ancient: ) is the largest and most populous of the Greek islands, the 88th largest island in the world and the fifth largest island in the Mediterranean Sea, after Sicily, Sardinia, Cyprus, and ...
, jasper was carved to produce seals circa 1800 BC, as evidenced by archaeological recoveries at the palace of Knossos
Knossos (also Cnossos, both pronounced ; grc, Κνωσός, Knōsós, ; Linear B: ''Ko-no-so'') is the largest Bronze Age archaeological site on Crete and has been called Europe's oldest city.
Settled as early as the Neolithic period, the na ...
.
Although the term jasper is now restricted to opaque quartz, the ancient ''iaspis'' was a stone of considerable translucency including nephrite
Nephrite is a variety of the calcium, magnesium, and iron-rich amphibole minerals tremolite or actinolite (Aggregate (geology), aggregates of which also make up one form of asbestos). The chemical formula for nephrite is calcium, Ca2(magnesium, ...
.[ The jasper of antiquity was in many cases distinctly green, for it is often compared to ]emerald
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr. and Kammerling, Robert C. (1991) ''Gemology'', John Wiley & Sons, New York, p ...
and other green objects. Jasper is referred to in the '' Nibelungenlied'' as being clear and green. The jasper of the ancients probably included stones which would now be classed as chalcedony, and the emerald-like jasper may have been akin to the modern chrysoprase
Chrysoprase, chrysophrase or chrysoprasus is a gemstone variety of chalcedony (a cryptocrystalline form of silica) that contains small quantities of nickel. Its color is normally apple-green, but varies to deep green. The darker varieties of chry ...
. The Hebrew word may have designated a green jasper. Flinders Petrie suggested that the ''odem'', the first stone on the High Priest's breastplate, was a red jasper, whilst ''tarshish'', the tenth stone, may have been a yellow jasper.
Types
Jasper is an 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 lingui ...
rock of virtually any colour stemming from the mineral content of the original sediments or ash. Patterns arise during the consolidation process forming flow and depositional patterns in the original silica-rich sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
or volcanic ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcano, volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used t ...
. Hydrothermal circulation
Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...
is generally thought to be required in the formation of jasper.
Jasper can be modified by the diffusion of minerals along discontinuities providing the appearance of vegetative growth, i.e., dendritic
Dendrite derives from the Greek word "dendron" meaning ( "tree-like"), and may refer to:
Biology
*Dendrite, a branched projection of a neuron
*Dendrite (non-neuronal), branching projections of certain skin cells and immune cells
Physical
* Dendr ...
. The original materials are often fractured and/or distorted, after deposition, into diverse patterns, which are later filled in with other colorful minerals. Weathering, with time, will create intensely colored superficial rinds.
The classification and naming of jasper varieties presents a challenge. Terms attributed to various well-defined materials includes the geographic locality where it is found, sometimes quite restricted such as "Bruneau" (a canyon) and "Lahontan" (a lake), rivers and even individual mountains; many are fanciful, such as "forest fire" or "rainbow", while others are descriptive, such as "autumn" or "porcelain". A few are designated by the place of origin such as a brown Egyptian or red African.
Banded iron formations
Jasper is the main component in the silica-rich parts of banded iron formations (BIFs) which indicate low, but present, amounts of dissolved oxygen in the water such as during the Great Oxidation Event or snowball earths. The red bands, typically more competent than the hematite layers surrounding it, are made of microcrystalline red chert, also called jasper.
Picture jaspers
Picture jaspers exhibit combinations of patterns resulting in what appear to be scenes or images, when seen on a cut section. Such patterns include banding from flow or depositional patterns (from water or wind), as well as dendritic or color variations. Diffusion from a center produces a distinctive orbicular Orbicular is an adjective meaning "circular"
Orbicular may also refer to:
* Orbicular leaf, a plant leaf shape
* Orbicularis oculi muscle, a muscle around the eye
* Orbicularis oris muscle, a muscle around the mouth
* Orbicular batfish, a specie ...
appearance, i.e., leopard skin jasper or linear banding from a fracture as seen in liesegang
Liesegang rings () are a phenomenon seen in many, if not most, chemical systems undergoing a precipitation reaction under certain conditions of concentration and in the absence of convection. Rings are formed when weakly soluble salts are produc ...
jasper. Healed, fragmented rock produces breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix.
The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of di ...
ted (broken) jasper.
While these "picture jaspers" can be found all over the world, specific colors or patterns are unique to the geographic region from which they originate. One source of the stone is Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, especially in Purbalingga
Purbalingga ( Javanese: ꦥꦸꦂꦧꦭꦶꦁꦒ) is a town and district in Central Java Province of Indonesia and the seat of Purbalingga Regency
Villages
The district includes 11 urban villages (''kelurahan'') and 2 rural villages (''desa'') ...
district. From the US is Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
's Biggs jasper
Biggs jasper is a variety of the mineral jasper. It is a "picture jasper" – a jasper that exhibits particular patterns and colors – and is used as an opaque gemstone. It exhibits intricate, shell- or layer-like patterns in shades of brown ran ...
and Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...
's Bruneau jasper
Bruneau jasper is a variety of the mineral jasper. It is a "picture jasper" – a jasper that exhibits particular patterns and colors – and is used as an opaque gemstone.
The stone exhibits layered patterns of brown, reddish brown and cream c ...
from the Bruneau River canyon are particularly fine examples. Other examples can be seen at Ynys Llanddwyn in Wales
Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
. A remarkable, pale, blue-green jasper, with patterns somewhat resembling those of malachite
Malachite is a copper carbonate hydroxide mineral, with the formula Cu2CO3(OH)2. This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures ...
, occurs in a deposit at Ettutkan Mountain, Staryi Sibay, Bashkortostan
The Republic of Bashkortostan or Bashkortostan ( ba, Башҡортостан Республикаһы, Bashqortostan Respublikahy; russian: Республика Башкортостан, Respublika Bashkortostan),; russian: Респу́блик ...
, Russia. (The town of Sibay, in the far south of the Ural Mountains
The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through western ...
, near the border with Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
, is noted for its colossal, open-cast copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
mine.)
Basanite and other types of touchstone
Basanite is a deep velvety-black variety of amorphous quartz, of a slightly tougher and finer grain than jasper, and less splintery than hornstone. It was the ''Lydian stone'' or ''touchstone'' of the ancients. It is mentioned and its use described in the writings of Bacchylides about 450 B.C., and was also described by Theophrastus
Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Botany'', Routledge ...
in his book ''On Stones'' (Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...
title: Περὶ λίθων: ''Peri Lithon''), a century later. It is evident that the touchstone that Pliny had in mind when he wrote about it was merely a dense variety of basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
.
Basanite (not to be confused with bassanite), ''Lydian stone'', and radiolarite (a.k.a. lydite or flinty slate) are terms used to refer to several types of black, jasper-like rock (also including tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
s, chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...
s and siltstone
Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...
s) which are dense, fine-grained and flinty / cherty in texture and found in a number of localities. The "Lydian Stone" known to the Ancient Greeks
Ancient Greece ( el, Ἑλλάς, Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( AD 600), that comprised a loose collection of cultu ...
is named for the ancient kingdom of Lydia
Lydia (Lydian language, Lydian: 𐤮𐤱𐤠𐤭𐤣𐤠, ''Śfarda''; Aramaic: ''Lydia''; el, Λυδία, ''Lȳdíā''; tr, Lidya) was an Iron Age Monarchy, kingdom of western Asia Minor located generally east of ancient Ionia in the mod ...
in what is now western Turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
. A similar rock type occurs in New England
New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...
. Such rock types have long been used for the making of touchstones to test the purity of precious metal
Precious metals are rare, naturally occurring metallic chemical elements of high economic value.
Chemically, the precious metals tend to be less reactive than most elements (see noble metal). They are usually ductile and have a high lustre. ...
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
s, because they are hard enough to scratch such metals, which, if drawn (scraped) across them, show to advantage their metallic streaks of various (diagnostic) colours, against the dark background. There are, confusingly, not one but two rocks called basanite, one being a black form of jasper and the other
Other often refers to:
* Other (philosophy), a concept in psychology and philosophy
Other or The Other may also refer to:
Film and television
* ''The Other'' (1913 film), a German silent film directed by Max Mack
* ''The Other'' (1930 film), a ...
a black volcanic rock closely akin to basalt. Add to this the fact that many different rock types - having in common the colour black and a fine texture - have, over the ages, been pressed into service as touchstones and it will be seen that there is ample scope for confusion in this petrology
Petrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together ...
- and mineralogy
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...
-related field of study.
Gallery
References
External links
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