Dolomite
Mineral CaMg(CO3)2
Also called Pearl spar
About it
Curved, saddle-shaped rhombs with a pearly shine; it fizzes in cold acid only when powdered, unlike calcite. Fine clear crystals come from Eugui, Spain, and saddle-shaped clusters from Missouri and Ohio.
- Type
- Mineral
- Group
- Carbonate, dolomite group
- Formula
- CaMg(CO3)2
- Hardness (Mohs)
- 3.5–4
- Specific gravity
- 2.84–2.86
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Trigonal
- Colours
- white, colourless, pink, grey, brown, yellowish
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect rhombohedral
Typical values: real specimens vary. For more, see mindat.org.