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Jadeite is a pyroxene mineral with composition Na Al Si 2 O 6.It is hard (Mohs hardness of about 6.5 to 7.0), very tough, and dense, with a specific gravity of about 3.4.It is found in a wide range of colors, but is most often found in shades of green or white.
The chain silicate structure of the pyroxenes offers much flexibility in the incorporation of various cations and the names of the pyroxene minerals are primarily defined by their chemical composition. Pyroxene minerals are named according to the chemical species occupying the X (or M2) site, the Y (or M1) site, and the tetrahedral T site.
The pyroxene group consists of 21 mineral species. [120] Pyroxenes have a general structure formula of XY(Si 2 O 6), where X is an octahedral site, while Y can vary in coordination number from six to eight. Most varieties of pyroxene consist of permutations of Ca 2+, Fe 2+ and Mg 2+ to balance the negative charge on the backbone. Pyroxenes are ...
The word pyroxene, in turn comes from the Greek words for fire (πυρ) and stranger (ξένος). Pyroxenes were named this way because of their presence in volcanic lavas, where they are sometimes seen as crystals embedded in volcanic glass ; it was assumed they were impurities in the glass, hence the name "fire strangers".
Diopside is a monoclinic pyroxene mineral with composition MgCaSi 2 O 6. It forms complete solid solution series with hedenbergite (FeCaSi 2 O 6) and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class.
Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present. Anorthosites are of enormous geologic interest, because it is still not fully understood how they form. Most models involve separating plagioclase crystals based on their density. Plagioclase crystals are usually less dense than magma; so, as plagioclase ...
Indigo dye – Indigo, a blue pigment and a dye, was used in India, which was also the earliest major centre for its production and processing. [2] The Indigofera tinctoria variety of Indigo was domesticated in India. [2] Indigo, used as a dye, made its way to the Greeks and the Romans via various trade routes, and was valued as a luxury ...
Hedenbergite has a number of specific properties. Its hardness is usually between five and six with two cleavage plains and conchoidal fracture. Color varies between black, greenish black, and dark brown with a resinous luster. Hedenbergite is a part of a pyroxene solid solution chain consisting of diopside and augite, and is the iron rich end ...