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.

ABC of mining