Last edited 12 Nov 2018



Gypsum is a soft sulfate mineral with the chemical formula CaSO4·2H2O, also known as calcium sulfate dihydrate. It is comprised of calcium, sulphur bound to oxygen, and water. It is an abundant mineral in sedimentary rocks that has been mined and used for construction and and as a fertilizer since the time of Ancient Egypt.

Pure gypsum is typically white, although impurities create a wide range of different colours. Gypsum is moderately water soluble but exhibits retrograde solubility, meaning it becomes less soluble at higher temperatures. It is fire resistant and is effective at preventing the passage of sound.

In terms of production, gypsum rock is mined or quarried and then crushed and ground into a fine powder. A process of calcining heats the powder, driving off most of the chemically-combined water.

This base gypsum is used for a wide variety of applications:

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