Calcite

Name:
Calcite
Detailed information:

M Formula:	CaCO3
Properties:
Colorless, white, and various-colored crystals; vitreous to earthy luster; good cleavage in three directions. D 2.72, Mohs hardness 2. May contain small amounts of magnesium, iron, manganese, and zinc. Reacts with acids to evolve carbon dioxide.
Use:
Phosphor. Iceland spar is used in optical instruments.