Gypsum
Formula:CaSO4·2H2O
Colour:Colourless to white, often tinged other hues due to impurities; colourless in transmitted light.
Classification:Sulfates
Lustre:Vitreous, Sub-Vitreous, Silky, Pearly, Dull
Crystal System:Monoclinic
Hardness:2
Specific Gravity:2.31-2.33