Dolomite

(Geol.) [Named after DOLOMIEU, q. v.] See PERMIAN and MAGNESIAN LIMESTONE. -( Min.) A specific name for the rhombohedral compounds of carbonate of lime and magnesia. It includes the varieties Pearl Spar, Bitter Spar, Mesitine Spar, and Breunnerite. As a rock, the name is given to limestones containing carbonate of magnesia; those varieties that approach nearest in composition to equivalent combinations of the two carbonates yielding the most durable building-stones. In the Tyrol, Canada, and other mountainous districts, local ma es of limestone are found to be changed into crystalline D. over extensive areas.