What is Dolomite?
Dolomite is a calcium-magnesium carbonate that forms rhombohedral crystals, sedimentary rock beds and distinctive saddle-shaped aggregates.
Mineralogy and structure
The reference formula is CaMg(CO3)2. Dolomite is trigonal and commonly forms curved or saddle-shaped crystals. It is also a major rock-forming mineral and should be distinguished from dolostone, the rock.
Colour and appearance
Typical colours include colourless, white, grey, pink, brown, green. Its rhombohedral, saddle-shaped, granular habit and vitreous, pearly lustre are useful descriptive features, but colour alone is not diagnostic.
Formation and localities
Dolomite forms in or is associated with carbonate sedimentary rocks, hydrothermal veins, marbles and replacement zones. Important documented localities include Italy, Spain, Switzerland, the United States, Mexico and many carbonate basins worldwide.
Collecting and care
Dolomite is best kept as a labelled reference or collector specimen. Protect fragile crystals from impact and avoid cutting or grinding unknown material. Lead-, arsenic-, vanadium- and copper-bearing specimens are for display and careful handling only.
Dolomite in popular symbolism
Some modern crystal guides associate Dolomite with zodiac signs or symbolic themes based on colour, locality or collecting tradition. These associations vary between sources and are cultural interpretations, not mineralogical or medical properties.
