Calcite vs Dolomite
| Property | Calcite | Dolomite |
|---|---|---|
| สูตรเคมี | CaCO3 | CaMg(CO3)2 |
| ระบบผลึก | Trigonal | Trigonal |
| หมวดหมู่แร่ธาตุ | 05 Carbonates and Nitrates | 05 Carbonates and Nitrates |
| ความแข็งโมห์ส | 3.0 | 3.5-4.0 |
| สี | Colorless, white, yellow, orange, blue, green | Colorless, white, pink, gray, brown |
| ความวาว | Vitreous | Vitreous |
| สีเส้นขูด | White | White |
| ความโปร่งใส | Transparent | Transparent |
| การแตกเรียบ | Perfect rhombohedral {1011} | Perfect rhombohedral {1011} |
| รอยแตก | 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.