What is Calcium Sulphate?

Calcium Sulphate Poorly Soluble Powder

Calcium sulphate comes from the minerals anhydrite or gypsum. 

Angelite is a blue variety of anhydrite from Peru.

Gypsum which dissolves over time in water is found in sedimentary rocks.  

Calcium sulphate occurs naturally in two forms.  One is hydrated (with water) and the other is anhydrous (without water).

Anhydrous calcium sulphate comes from the mineral anhydrite.  The hydrated variety is gypsum.  

When mixed with water and allowed to dry gypsum hardens to form a solid structure that doesn't crack.

Calcium sulphate can either be found as a white odourless powder or as crystals which may be tinged with colour.  The colour comes from various impurities.

This poorly soluble white powder is used extensively in industry for a wide variety of purposes some of which include;

• The production of plaster of Paris

• As a food additive

• In dentistry particularly for the use of moulds/casts 

• In the building trade for plaster and cement

• In agriculture as a soil improver

• In pharmaceuticals as a calcium supplement

• To increase brightness and whiteness in paper products