Dolomite, found chiefly in rock masses as dolomitic limestone, but occurring sometimes in veins. It has a hardness of 3.5 to 4 and a specific gravity of 2.85. Dolomite crystallizes in the hexagonal system. It is usually colorless, white, or pink like this one, but may be brown, black, or green, depending on the impurities present. In the United States it is found in many localities in Arkansas, Vermont, Rhode Island, New York, and New Jersey.