Definition - What does Anhydrite mean?
Anhydrite, also known as Anhydrous Calcium Sulfate, is a mineral found in the sedimentary rock beds trapped in the zeolite occurrences and gangue in ore veins. Its chemical formula is CaSO4. When cut, its atoms bonding are in the form of orthorhombic crystal system which has a perfect cleavage of three directions parallel to its three planes of symmetry.
Petropedia explains Anhydrite
Anhydrite has a hardness of 3.5 and its specific gravity is 2.9. Its appearance is usually white (pearl) in color, but it can also be found in blue, grey or purplish colors. When it comes in contact with water, it chemically reacts and transforms to Gypsum (CaSO42H2O). It is commonly associated with Sulfides (such as galena, chalcopyrite, pyrite and molybdenite), halite and calcite.
Anhydrite is a very brittle mineral and can be fractured easily. The diaphaneity of Anhydrite is transparent, Sub transparent and translucent.