Anhydrite

Info: Anhydrite is calcium sulfate. Often is found in whole, grain-like or fibre agregates, which can be found very often in large numbers. Anhydrite is usually greyish, but it can be reddish sometimes. The most priced are the rare purpule anhydrites. The mineral is translucent to transparent and have glassy to pearl luster. Its not very hard and it is of medium weight.

How to recognize: Anhydrite is dissolved in hydrochloric acid, even in water. If exposed to air, anhydrite absorbs water and transforms himself to gypsum. In this case he enlarges up to 60% of its original size.

Found: Anhydrite was found in Swizerland, Austria, Germany and Italy. In Czech Republic was found in Krušný Hory.