|
Rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite. Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion. Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum. Rutile derives its name from the Latin ('red'), in reference to the deep red color observed in some specimens when viewed by transmitted light. Rutile was first described in 1803 by Abraham Gottlob Werner using specimens obtained in Horcajuelo de la Sierra, Madrid (Spain), which is consequently the type locality. Occurrence Rutile is a comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium Dioxide
Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound derived from titanium with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or Colour Index International, CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen, and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million tonnes. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at a price of $13.2 billion. Structure In all three of its main dioxides, titanium exhibits Octahedral molecular geometry, octahedral geometry, being bonded to six oxide anions. The oxides in turn are bonded to three Ti centers. The overall crystal structures of rutile and anatase are tetragonal in symmetry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatase
Anatase is a metastable mineral form of titanium dioxide (TiO2) with a Tetragonal crystal system, tetragonal crystal structure. Although colorless or white when pure, anatase in nature is usually a black solid due to impurities. Three other Polymorphism (materials science), polymorphs (or mineral forms) of titanium dioxide are known to occur naturally: brookite, akaogiite, and rutile, with rutile being the most common and most Chemical stability, stable of the bunch. Anatase is formed at relatively low temperatures and found in minor concentrations in Igneous rock, igneous and Metamorphic rock, metamorphic rocks. Glass coated with a thin film of TiO2 shows Anti-fog, antifogging and Self-cleaning surfaces, self-cleaning properties under ultraviolet radiation. Anatase is always found as small, isolated, and sharply developed crystals, and like rutile, it crystallizes in a Tetragonal crystal system, tetragonal system. Anatase is metastable at all temperatures and pressures, with ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium
Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of minerals, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide (TiO2), is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and cata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brookite
Brookite is the Orthorhombic crystal system, orthorhombic variant of titanium dioxide (TiO2), which occurs in four known natural Polymorphism (materials science), polymorphic forms (minerals with the same composition but different structure). The other three of these forms are akaogiite (Monoclinic crystal system, monoclinic), anatase (Tetragonal crystal system, tetragonal) and rutile (Tetragonal crystal system, tetragonal). Brookite is rare compared to anatase and rutile and, like these forms, it exhibits Photocatalysis, photocatalytic activity. Brookite also has a larger Crystal structure, cell volume than either anatase or rutile, with 8 TiO2 groups per unit cell, compared with 4 for anatase and 2 for rutile.Anatase and Brookite . Wikis.lib.ncsu.edu (2007-05-08). Retrieved on 2011-10-14. Iron (Fe), tantalum (Ta) and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxide Minerals
The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. Minerals with complex anion groups such as the Silicate mineral, silicates, Sulfate mineral, sulfates, carbonate mineral, carbonates and Phosphate mineral, phosphates are classed separately. Simple oxides *XO form **Periclase group ***Periclase ***Manganosite **Zincite group ***Zincite ***Bromellite ***Tenorite ***Litharge * form **Cuprite **Ice * form **Hematite group ***Corundum ***Hematite ***Ilmenite * form **Rutile group ***Rutile ***Pyrolusite ***Cassiterite **Baddeleyite **Uraninite **Thorianite * form **Spinel group ***Spinel ***Gahnite ***Magnetite ***Franklinite ***Chromite **Chrysoberyl **Columbite *Hydroxide subgroup: **Brucite **Manganite **Romanèchite **Goethite group: ***Diaspore ***Goethite Nickel–Strunz class 4: oxides Internationa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxide Mineral
The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. Minerals with complex anion groups such as the silicates, sulfates, carbonates and phosphates are classed separately. Simple oxides *XO form **Periclase group *** Periclase *** Manganosite **Zincite group *** Zincite *** Bromellite *** Tenorite *** Litharge * form ** Cuprite **Ice * form **Hematite group ***Corundum ***Hematite *** Ilmenite * form **Rutile group ***Rutile *** Pyrolusite *** Cassiterite ** Baddeleyite ** Uraninite ** Thorianite * form **Spinel group ***Spinel ***Gahnite ***Magnetite *** Franklinite ***Chromite ** Chrysoberyl ** Columbite *Hydroxide subgroup: **Brucite ** Manganite ** Romanèchite **Goethite group: *** Diaspore ***Goethite Nickel–Strunz class 4: oxides IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birefringence
Birefringence, also called double refraction, is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are described as birefringent or birefractive. The birefringence is often quantified as the maximum difference between refractive indices exhibited by the material. Crystals with non-cubic crystal structures are often birefringent, as are plastics under mechanical stress. Birefringence is responsible for the phenomenon of double refraction whereby a ray of light, when incident upon a birefringent material, is split by polarization into two rays taking slightly different paths. This effect was first described by Danish scientist Rasmus Bartholin in 1669, who observed it in Iceland spar (calcite) crystals which have one of the strongest birefringences. In the 19th century Augustin-Jean Fresnel described the phenomenon in terms of polarization, understanding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetragonal Crystal System
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square base (''a'' by ''a'') and height (''c'', which is different from ''a''). Bravais lattices There are two tetragonal Bravais lattices: the primitive tetragonal and the body-centered tetragonal. The body-centered tetragonal lattice is equivalent to the primitive tetragonal lattice with a smaller unit cell, while the face-centered tetragonal lattice is equivalent to the body-centered tetragonal lattice with a smaller unit cell. Crystal classes The point groups that fall under this crystal system are listed below, followed by their representations in international notation, Schoenflies notation, orbifold notation, Coxeter notation and mineral examples.Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lustre (mineralogy)
Lustre (Commonwealth 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 implies radiance, gloss, or brilliance. A range of terms are used to describe lustre, such as ''earthy'', ''metallic'', ''greasy'', and ''silky''. Similarly, the term ''vitreous'' (derived from the Latin for glass, ''vitrum'') refers to a glassy lustre. A list of these terms is given below. Lustre varies over a wide continuum, and so there are no rigid boundaries between the different types of lustre. (For this reason, different sources can often describe the same mineral differently. This ambiguity is further complicated by lustre's ability to vary widely within a particular mineral species). The terms are frequently combined to describe intermediate types of lustre (for example, a "vitreous greasy" lustre). Some minerals exhib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abraham Gottlob Werner
Abraham Gottlob Werner (; 25 September 174930 June 1817) was a German geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ... who set out an early theory about the Stratigraphy, stratification of the Earth's crust and propounded a history of the Earth that came to be known as Neptunism. While most tenets of Neptunism were eventually set aside, Werner is remembered for his demonstration of Succession (geology), chronological succession in rocks; for the zeal with which he infused his pupils; and for the impulse he thereby gave to the study of geology. He has been called the "father of German geology". Life Werner was born in Wehrau (now Osiecznica, Lower Silesian Voivodeship), a village in Prussian Silesia. His family had been involved in the mining industry for many years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light
Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequency, frequencies of 750–420 terahertz (unit), terahertz. The visible band sits adjacent to the infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively ''optical radiation''. In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity (physics), intensity, propagation direction, frequency or wavelength spectrum, and polarization (waves), polarization. Its speed of light, speed in vacuum, , is one of the fundamental physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Locality (geology)
Type locality, also called type area, is the locality where a particular rock type, stratigraphic unit or mineral species is first identified. If the stratigraphic unit in a locality is layered, it is called a stratotype, whereas the standard of reference for unlayered rocks is the type locality. The concept is similar to type site in archaeology. Examples of geological type localities Rocks and minerals * Aragonite: Molina de Aragón, Guadalajara, Spain * Autunite: Autun, France * Benmoreite: Ben More (Mull), Scotland * Blairmorite: Blairmore, Alberta, Canada * Boninite: Bonin Islands, Japan * Comendite: Comende, San Pietro Island, Sardinia * Cummingtonite: Cummington, Massachusetts * Dunite: Dun Mountain, New Zealand * Essexite: Essex County, Massachusetts, US * Fayalite: Horta, Fayal Island, Azores, Portugal * Harzburgite: Bad Harzburg, Germany * Icelandite: Thingmuli (Þingmúli), Iceland * Ijolite: Iivaara, Kuusamo, Finland * Kimberlite: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
