dolomita

Dolomite (Spanish: dolomita) is a carbonate mineral with the chemical formula CaMg(CO3)2. It crystallizes in the trigonal (rhombohedral) system and typically forms white to gray crystals or massive, granular occurrences. The mineral was named after the French geologist Déodat Gratet de Dolomieu.

Dolomite forms mainly through diagenetic alteration of limestone, a process known as dolomitization, in which magnesium-rich fluids replace some calcium in the rock. It is common in sedimentary basins worldwide and often occurs in beds interlayered with limestone.

In nature, dolomite can contain impurities such as iron, manganese, or strontium, which may give it pink, brown, or gray colors. The rock formed from degraded or compacted dolomite is called dolostone, a major carbonate rock in many sedimentary sequences.

Industrial and practical uses include the production of magnesium oxide, as a source of magnesium in refractories, and in cement and lime production. Dolomite is also used as a decorative stone and as a soil conditioner to supply calcium and magnesium in agriculture.

Identification notes: dolomite is similar in appearance to calcite but differs in chemistry and physical properties; it reacts with cold, dilute acids only when powdered. It has a Mohs hardness of about 3.5 to 4 and shows rhombohedral cleavage.