Dolomite
CaMg(CO3)2IMA symbol: Dolgrandfathered
Dolomite is a carbonate or nitrate mineral with the formula CaMg(CO3)2, crystallizing in the trigonal system. It has a Mohs hardness of 3, typically white, black, brown or gray in color, with a pearly or vitreous luster, a specific gravity of 2.8-2.9. Its streak is white.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | R -3 :H |
| Cell (Å, °) | a = 4.795, b = 4.795, c = 15.87; α = 90, β = 90, γ = 120 |
| Cell volume | 315.998 ų, Z = 3 |
| Axial ratios | 1.0000:1:3.3097calculated from COD 1517797 |
| Source structure | COD 1517797 (Societas Scientiarum Fennica. Commentationes Physicomathematicae II, 1925) — 1 of 58 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.869 | 2.184 | 1.776 | 1.79 | 2.009 | 2.398 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 25.2 | 19.7 | 18.4 | 14.3 | 12.2 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 1517797; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.907 g/cm³calculated from COD 1517797 |
|---|---|
| Hardness (Mohs) | 3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.8-2.9 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, brown, gray, green, red, rose, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
| Luster | pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 184.4 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Ca 21.73%, Mg 13.18%, C 13.03%, O 52.06% |
Classification
| Nickel-Strunz (10th) | 5.AB.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 5.AB.10Wikidata (CC0) |
| Dana (8th) | 14.2.1.1Wikidata (CC0) |