spinel


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spinel,

magnesium aluminum oxide, MgAl2O4, a mineral crystallizing in the isometric system, usually as octahedrons. It occurs as an accessory mineral in basic igneous rocks, in aluminum-rich metamorphic rocks, and in contact-metamorphosed limestones. Common spinel usually ranges in color from dark green to brown or black, but transparent red, blue, and green varieties are found and are used as gemstones; Myanmar and Sri Lanka are the principal producing countries. Much gem-quality spinel is now produced synthetically.

spinel

[spə′nel]
(mineralogy)
MgAl2O4 A colorless, purplish-red, greenish, yellow, or black mineral, usually forming octahedral crystals, and characterized by great hardness; used as a gemstone.
A group of minerals of general formula AB2O4, where A is magnesium, ferrous iron, zinc, or manganese, or a combination of them, and B is aluminum, ferric iron, or chromium.
References in periodicals archive ?
ArmorLine, a South Carolina-based company part of the Defense Venture Group, has developed an optical grade transparent spinel ceramic that allows to produce transparent armour with a considerable weight saving.
Spinels are minerals with a cubic structure that are highly conductive.
Some of manganite nanocatalyst compounds with spinel structure were synthesized in the research through self-combusting sol-gel method, and their physicochemical properties were identified through various techniques.
There are raspberry Tanzanian spinels and Nigerian yellow tourmalines I lust after for the collection.
Lithium titanate spinel oxide, notably Li<sub>4Ti<sub>5O<sub>12, is an attractive anode material for lithium-ion batteries.
These splendid unique pieces represent a sophisticated marriage of simplicity yet at the same time utmost complexity: the two halves of both the purist bangle and matching ring of 18-carat white gold, feature dazzlingly white diamonds in contrast with magically dark spinel precious stones.
The x-ray diffraction analysis on the composition of the surface layer of the corrosion products, formed on the specimens of the ZhS-32 alloy after testing in synthetic sol at both temperatures show that the main phase components are the chromium spinel NiO x [Cr.
A higher number of spinel inclusions were detected in the as-melted bath condition than in the rotary degassed or rotary flux injected molten bath.
concentrate, whilst others contained diamond inclusion spinel.
s nano-structured lithium titanate spinel electrode materials.