Dolomite - CaMg(CO₃)₂

Habit: Colorless, white, yellow, brown or pale pink. Crystals tabular and may exhibit curved faces; also columnar, stalatitic, granular or massive. Vitreous to pearly luster; transparent to translucent. White streak.

Environment: An important sedimentary and metamorphic mineral, the principal mineral in dolostones and metadolostones and an important mineral in limestones and marbles where calcite is the principal mineral present. Also found as a gangue in hydrothermal veins, forming crystals in cavities, and in serpentinites and similar rocks.

Etymology: Named after Dieudonné Sylvain Guy Tancrède de Gratet de Dolomieu, usually known as Déodat de Dolomieu (1750- 1801), a French geologist and naturalist who contributed to early descriptions of the species in dolostone.