Diopside (MgCaSi2O6) is a monoclinic pyroxene mineral. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class. It measures 6 on Moh’s scale of hardness. It varies from transparent to translucent crystals.

Diopside of gemstone quality is found in two forms: the black star diopside and the chrome diopside in which chromium is present giving it a rich green color. Chrome diopside is relatively soft to scratch since its harness is only 5.5 to 6.5 on the Moh’s scale of hardness.

Violane is a variety of diopside rich in manganese and varies from violet to light blue color. Diopside derives its name from the Greek words ‘dis’, meaning “twice”, and òpsè meaning “face” with reference to the two ways of orienting the vertical prism. Diopside was first described around 1800.

Diopside based ceramics have potential applications in various technological areas. ‘Silceram’- a diopside based glass-ceramic was produced in 1980s from blast furnace slag and other waste products.
Diopside based ceramics and glass-ceramics have potential applications in the field of biomaterials, nuclear waste immobilization and sealing materials in solid oxide fuel cells.