This is a beautiful thumbnail size Blue Topaz, Hammerhead, from Mwami Hurungwe, Zimbabwe.
Crystal Dimensions:
1.5cm (0.5”) x 1.5cm (0.5”)
Weight:
2.2 grams
Topaz is a silicate mineral of aluminium and fluorine.
The chemical formula is
Al₂SiO₄(F, OH)₂