Gypsum is a calcium sulphate mineral in non-metallic sulphates.

It is widely used:

• in building materials, such as cement retarder, gypsum products for construction and cementing materials;
• as the soil improver, fertilizer and pesticide in agriculture;
• in papermaking, paint, rubber, ceramics, plastics, textile, food, arts and crafts, culture, education and medicine;
• as raw materials for the manufacture of sulfuric acid and ammonium sulfate in the absence of other sulfur resources.

Two main classes of gypsum ore

Generally speaking, gypsum refers to two minerals, gypsum and anhydrite. They are often produced together and can be transformed into each other under certain geological effects.

 

Types	Gypsum (Dihydrate gypsum or Plaster)	Anhydrite
Chemical formula	CaSO4·2H2O	CaSO4
Chemical composition	32.6% of CaO, 46.5% of SO3, 0.9% of H2O2+	41.2% of CaO and 58.8% of SO3
Crystal system	monoclinic	orthorhombic
Crystal habit	tabular, dense massive, fibrous tabular	dense massive, granulous
Color	white, gray, red, brown	white, off-white
Luster	vitreous, silky	vitreous
Hardness	2	3～3.5
Density	2.3 g/cm3	2.8～3.0 g/cm3
Cleavage	{010} perfect	{010} perfect