Calcite vs Dolomite

Property Calcite Dolomite
化学式 CaCO3 CaMg(CO3)2
晶系 Trigonal Trigonal
矿物分类 05 Carbonates and Nitrates 05 Carbonates and Nitrates
莫氏硬度 3.0 3.5-4.0
颜色 Colorless, white, yellow, orange, blue, green Colorless, white, pink, gray, brown
光泽 Vitreous Vitreous
条痕色 White White
透明度 Transparent Transparent
解理 Perfect rhombohedral {1011} Perfect rhombohedral {1011}
断口 Conchoidal Subconchoidal

Key Differences

  • Calcite reacts strongly with cold dilute HCl; dolomite only reacts when powdered.
  • Dolomite contains both calcium and magnesium (CaMg(CO3)2); calcite is pure CaCO3.
  • Dolomite crystals often show distinctive curved saddle-shaped (baroque) faces; calcite does not.
  • Calcite has a slightly lower specific gravity (2.71) than dolomite (2.84–2.86).
  • Calcite is trigonal with scalenohedral and rhombohedral habits; dolomite is also trigonal but rarely forms good scalenohedral crystals.

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