Dolomite

Real mineral · common · CaMg(CO₃)₂

Calcium magnesium carbonate forming by replacement of limestone through magnesium-rich fluids. The process, called dolomitisation, is not fully understood. Reacts more slowly with acid than calcite, a useful field distinction.

Identity

Formula

CaMg(CO₃)₂

Chemical class

carbonate

Also known as

Bitter spar, Pearl spar

Crystallography

Crystal system

trigonal

Habits

rhombohedral, massive, granular

Fracture

subconchoidal

Physical properties

Mohs hardness

3.5

Density

2.85 g/cm³

Luster

vitreous, pearly

Colors

white, gray, pink, yellow, brown

Streak

white

Transparency

transparent, translucent

Geology

Origins

sedimentary, hydrothermal

Host rocks

limestone, evaporite

Associated minerals

Calcite, Quartz, Pyrite, Barite

Geography

worldwide

Classification

Rarity

common

Gem quality

No

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