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Lazurite

Chemical Formula

Na6Ca2(Al6Si6O24)(SO4,S,S2,S3,Cl,OH)2

Chemical Class

Silicates

Properties

Very strong blue color, sometimes violet, it presents unctuous to vitreous gloss, and it has 5 to 5.5 hardness.

Origin

Badakhshan Province, Afghanistan.

Curiosities

Lazurite is the blue component of the ‘precious stone’ (or, more precisely, decorative rock) Lapis-Lazuli, which is a rock comprised by Lazurite, Calcite and Pyrite. In the past, lazurite was widely used as blue and violet pigment, currently, it is replaced by synthetic products.

Use

Lapis-Lazuli rock has been mined since Ancient History in Afghanistan, and it is used in jewelry and sculpture fields. In India, it has been used since before 7000 B.C.

Source: MM Gerdau - Museu das Minas e do Metal -

ABC of mining

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