ANHYDRITE with undeterminated sulfate
ANHYDRITE with undeterminated sulfate
SPECIMEN NR #:625
Anhydrite, known as anhydrous calcium sulfate, has the chemical formula CaSO4 and crystallizes in the orthorhombic system, exhibiting perfect cleavage along three symmetry planes. Unlike the orthorhombic sulfates of barium (baryte) and strontium (celestine), it is not isomorphous with them despite similar chemical formulas. Well-formed crystals are relatively uncommon, as the mineral typically appears in cleavage masses. It has a Mohs hardness of 3.5 and a specific gravity of 2.9, with colors ranging from white to shades of grey, blue, or purple. The most developed cleavage exhibits a pearly luster, while other surfaces appear glassy. Anhydrite readily converts to gypsum (CaSO4·2H2O) upon contact with water, and this process is reversible; heating gypsum or calcium sulfate hemihydrate to approximately 200 °C (400 °F) can regenerate anhydrite under normal atmospheric conditions. In vein deposits, anhydrite is often found alongside calcite, halite, and various sulfides, including galena, chalcopyrite, molybdenite, and pyrite.
Specimen details
Specimen details
The numbers under "variant" are the measurements in mm and weight in grams. Where known, the origin of the specimen is mentioned. The number at the end, is the specimen number in our collection. Colours may vary, due to photography.
Care
Care
It's important to know that many minerals can be effectively cleaned with water. However, before using any cleaning methods, such as dissolvers or ultrasound, please take the time to research online. Improper use of these techniques could potentially harm your specimen.
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Shipping
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