Gypsum mainly contains CaSO4.H2O and is a sulphate mineral. It belongs to the monoclinic crystal system, and crystal twinning is common. It also appears in granular form (alabaster) and fibrous form (fibrous gypsum). Rosette gypsum blocks are called ‘Desert Rose’, whereas radial gypsum blocks are called ‘Daisy Gypsum’. It has a wide range of colours from colourless to white, grey, light green, pale yellow, light brown and pale red. It has flaky fractures, transparent to opaque diaphaneity, a vitreous or silky lustre in fibrous gypsum, and a pearly lustre on cleavage surfaces. It exists in the form of evaporite in hot spring areas and in clay layers. It is used for construction, making models and paper, and in the pharmaceutical sector.