Solid Mineral of the Week — Turquoise
Turquoise is an opaque blue to green mineral that is a hydrated phosphate of copper and aluminium with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It is rarely found in well-formed crystals but usually as an aggregate of microcrystals.

Turquoise as characteristically a cryptocrystalline mineral almost never forms single crystals with all of its properties highly variable. The finest of turquoise reaches a maximum Mohs hardness of just under 6.
The most desirable colour of turquoise is a sky blue or robin’s-egg blue. After blue, bluish green stones are preferred than green and yellowish green material. The demand for turquoise rises and falls over time. It can be highlighted that only three minerals such as gold, silver, and copper have a colour that is used more often in common language than turquoise.
Turquoise forms best in an arid climate, and that determines the geography of turquoise sources. Most of the world’s turquoise rough is currently produced in the southwestern United States, China, Chile, Egypt, Iran, and Mexico.
