Bassanite

Description

A naturally occurring mineral composed of an intermediate hydrate form of calcium sulfate that lies between the dihydrate (Gypsum) and the anhydrous (Anhydrite) states. Synthetic particles of bassanite occur when gypsum is calcined to form Plaster of Paris.

Physical and Chemical Properties

Microscopically similar to gypsum and plaster of Paris

Composition	CaSO4-xH2O
Refractive Index	1.55, 1.57