General Information:
Chemical Formula:
CaSO4
Composition:
(Molecular Weight = 136.14 gm)
Calcium 29.44 % Ca
Sulfur 23.55 % S
Oxygen 47.01 % O
Empirical Formula:
Ca(SO4)
Environment:
Sedimentary beds, gangue in ore veins, and in traprock zeolite occurrences.
Locality:
World wide occurrences where marine evaporite beds occur. Often interbedded with halite.
Name Origin:
From the Greek anhydros, meaning "waterless" (In contrast to Gypsum, which contains water).
Physical Properties:
Cleavage:
[010] Perfect, [100] Perfect, [001] Good
Color:
colorless, white, bluish white, violet white, or dark gray.
Density:
2.96 - 2.98, Average = 2.97
Diaphaniety:
Transparent to Subtransparent to translucent
Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Massive - Fibrous - Distinctly fibrous fine-grained forms., Plumose - "Mica-like" minerals forming agg regates of plume-like forms.
Hardness:
3.5 - Copper Penny
Luminescence:
None.
Luster:
Vitreous - Pearly
Streak:
white
More details...