; Dolomite is a carbonate mineral.This large specimin is from a local mine. Dolomite is calcium magnesium carbonate, a common sedimentary rock that is transformed into a mineral mineral. Dolomite is also called dolomitic limestone. The amount of calcium and magnesium in most specimens is equal, but occasionally one element may have a slightly greater presence than the other. Small amounts of iron and manganese are sometimes also present. Dolomite is used to make magnesia, which is used in medical applications, used as an ornamental and structural stone, in metallurgy for extracting certain metals from their ores, and is used in the chemical industry in the preparation of magnesium salts. PHYSICAL CHARACTERISTICS: Color is often pink or pinkish and can be colorless, white, yellow, gray or even brown or black when iron is present in the crystal. Luster is pearly to vitreous to dull. Transparency crystals are transparent to translucent. Cleavage is perfect in three directions forming rhombohedrons. Hardness is 3.5-4 Specific Gravity is 2.86 (average) Streak is white. Other Characteristics: Unlike calcite, effervesces weakly with warm acid or when first powdered with cold HCl. Dolomite is found in Midwestern quarries of the USA; Ontario, Canada; Switzerland; Spain and in Mexico, along with many other places in the world. Best Field Indicators are typical pink color, crystal habit, hardness, slow reaction to acid, density and luster. The photo at left is White Dolomite, from California.