Dolomite
Dolomite is a calcium magnesium carbonate and major rock-forming mineral. It's the principal mineral in dolostone (dolomite rock) and is closely related to calcite. The mineral is named after the Dolomite Alps of Italy. Missouri produces exceptional curved "saddle" dolomite crystals from hydrothermal veins — the distinctive curved faces (due to variable composition during growth) are immediately recognizable.
Physical Properties
Chemical Formula
CaMg(CO₃)₂
Hardness (Mohs)
3.5–4
Color
White, gray, pink, yellow, brown
Luster
Vitreous to pearly
Crystal System
Hexagonal (trigonal)
Streak
White
Cleavage
Perfect rhombohedral (3 directions)
Specific Gravity
2.84–2.86
🔍 Field Identification Tips
Very similar to calcite but does NOT fizz in cold HCl — only fizzes slowly in warm acid or when powdered. Slightly heavier than calcite (SG 2.84 vs 2.71). Perfect rhombohedral cleavage. Saddle or curved crystal faces are diagnostic for the mineral dolomite (not seen in calcite). Pink color is common.
Varieties & Forms
📍 Where to Find Dolomite in the US
Uses & Applications
Dimension stone, lime production, magnesium source, road aggregate, collectors specimens.
💰 Collector Value Guide
Common dolomite: $5–$30. Missouri baroque crystals: $30–$300. Pink dolomite on matrix: $50–$500.
Find Dolomite With Our Tools
Use the We Lick Rocks app to identify specimens, find dig sites, and connect with local rockhounds.