A

David

Darling

topaz

topaz

Topaz is an aluminum silicate mineral of composition Al2SiO4(F,OH)2, forming prismatic crystals in the orthorhombic system which are variable and unstable in color, and valued as gemstones. The best topazes come from Brazil, Siberia, and the United States.

 

Topaz belongs to the orthorhombic system.
Topaz belongs to the orthorhombic system. The unit cell is a straight prism on a rectangular base.