International Mineralogical Association in the context of "Biotite"

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⭐ Core Definition: International Mineralogical Association

Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. The IMA is affiliated with the International Union of Geological Sciences (IUGS).

The Association supports the activities of Commissions and Working Groups involved on certain aspects of mineralogical practice and facilitates interactions among mineralogists by sponsoring and organising meetings. In particular, the IMA holds its general meeting every four years. The last meeting was scheduled in 2022 in Lyon, France.

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👉 International Mineralogical Association in the context of Biotite

Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula K(Mg,Fe)3AlSi3O10(F,OH)2. It is primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous end-members include siderophyllite and eastonite. Biotite was regarded as a mineral species by the International Mineralogical Association until 1998, when its status was changed to a mineral group. The term biotite is still used to describe unanalysed dark micas in the field. Biotite was named by J.F.L. Hausmann in 1847 in honor of the French physicist Jean-Baptiste Biot, who performed early research into the many optical properties of mica.

Members of the biotite group are sheet silicates. Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. The term "iron mica" is sometimes used for iron-rich biotite, but the term also refers to a flaky micaceous form of haematite, and the field term Lepidomelane for unanalysed iron-rich Biotite avoids this ambiguity. Biotite is also sometimes called "black mica" as opposed to "white mica" (muscovite) – both may form in the same rocks, and in some instances side by side.

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In this Dossier

International Mineralogical Association in the context of Lime (material)

Lime is an inorganic material composed primarily of calcium oxides and hydroxides. It is also the name for calcium oxide which is used as an industrial mineral and is made by heating calcium carbonate in a kiln. Calcium oxide can occur as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The International Mineralogical Association recognizes lime as a mineral with the chemical formula of CaO. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering.

These materials are still used in large quantities in the manufacture of steel and as building and engineering materials (including limestone products, cement, concrete, and mortar), as chemical feedstocks, for sugar refining, and other uses. Lime industries and the use of many of the resulting products date from prehistoric times in both the Old World and the New World. Lime is used extensively for wastewater treatment with ferrous sulfate.

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International Mineralogical Association in the context of Argentite

In mineralogy, argentite (from Latin argentum 'silver') is cubic silver sulfide (Ag2S), which can only exist at temperatures above 173 °C (343 °F), 177 °C (351 °F), or 179 °C (354 °F). When it cools to ordinary temperatures it turns into its monoclinic polymorph, acanthite. The International Mineralogical Association has decided to reject argentite as a proper mineral.

The name "argentite" sometimes also refers to pseudomorphs of argentite: specimens of acanthite which still display some of the outward signs of the cubic crystal form, even though their actual crystal structure is monoclinic due to the lower temperature. This form of acanthite is occasionally found as uneven cubes and octahedra, but more often as dendritic or earthy masses, with a blackish lead-grey color and metallic luster.

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International Mineralogical Association in the context of Amphibole

Amphibole (/ˈæmfəbl/ AM-fə-bohl) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain SiO
4
tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is Amp. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association currently classifies amphiboles as a mineral supergroup, within which are two groups and several subgroups.

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International Mineralogical Association in the context of Hydroxylapatite

Hydroxyapatite (IMA name: hydroxylapatite) (Hap, HAp, or HA) is a naturally occurring mineral form of apatite with the formula Ca5(PO4)3(OH), often written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. It is the hydroxyl endmember of the complex apatite group. The OH ion can be replaced by fluoride or chloride, producing fluorapatite or chlorapatite. It crystallizes in the hexagonal crystal system. Pure hydroxyapatite powder is white. Naturally occurring apatites can, however, also have brown, yellow, or green colorations, comparable to the discolorations of dental fluorosis.

Up to 50% by volume and 70% by weight of human bone is a modified form of hydroxyapatite, known as bone mineral. Carbonated calcium-deficient hydroxyapatite is the main mineral of which dental enamel and dentin are composed. Hydroxyapatite crystals are also found in pathological calcifications such as those found in breast tumors, as well as calcifications within the pineal gland (and other structures of the brain) known as corpora arenacea or "brain sand".

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International Mineralogical Association in the context of Kamacite

Kamacite is an alloy of iron and nickel, which is found on Earth only in meteorites. According to the International Mineralogical Association (IMA) it is considered a proper nickel-rich variety of the mineral native iron. The proportion iron:nickel is between 90%:10% and 95%:5%; small quantities of other elements, such as cobalt or carbon may also be present. The mineral has a metallic luster, is gray and has no clear cleavage although its crystal structure is isometric-hexoctahedral. Its density is about 8 g/cm and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen.

The name was coined in 1861 and is derived from the Greek root καμακ- "kamak" or κάμαξ "kamaks", meaning vine-pole. It is a major constituent of iron meteorites (octahedrite and hexahedrite types). In the octahedrites it is found in bands interleaving with taenite forming Widmanstätten patterns. In hexahedrites, fine parallel lines called Neumann lines are often seen, which are evidence for structural deformation of adjacent kamacite plates due to shock from impacts.

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International Mineralogical Association in the context of Jade

Jade is an umbrella term for two different types of decorative rocks used for jewelry or ornaments. Jade is often referred to by either of two different silicate mineral names: nephrite (a silicate of calcium and magnesium in the amphibole group of minerals), or jadeite (a silicate of sodium and aluminum in the pyroxene group of minerals). Nephrite is typically green, although may be yellow, white or black. Jadeite varies from white or near-colorless, through various shades of green (including an emerald green, termed 'imperial'), to lavender, yellow, orange, brown and black. Rarely it may be blue.Both of these names refer to their use as gemstones, and each has a mineralogically more specific name. Both the amphibole jade (nephrite) and pyroxene jade are mineral aggregates (rocks) rather than mineral species.

Nephrite was deprecated by the International Mineralogical Association as a mineral species name in 1978 (replaced by tremolite). The name "nephrite" is mineralogically correct for referring to the rock. Jadeite is a legitimate mineral species, differing from the pyroxene jade rock. In China, the name jadeite has been replaced with fei cui, the traditional Chinese name for this gem that was in use long before Damour created the name in 1863.

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International Mineralogical Association in the context of Arsenopyrite

Arsenopyrite (IMA symbol: Apy) is an iron arsenic sulfide (FeAsS). It is a hard (Mohs 5.5–6) metallic, opaque, steel grey to silver white mineral with a relatively high specific gravity of 6.1.

When dissolved in nitric acid, it releases elemental sulfur. When arsenopyrite is heated, it produces sulfur and arsenic vapor. With 46% arsenic content, arsenopyrite, along with orpiment, is a principal ore of arsenic. When deposits of arsenopyrite become exposed to the atmosphere, the mineral slowly converts into iron arsenates. Arsenopyrite is generally an acid-consuming sulfide mineral, unlike iron pyrite which can lead to acid mine drainage.

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