Chalcocite
Cu2SIMA symbol: Ccgrandfathered
Chalcocite is a sulfide or sulfosalt mineral with the formula Cu2S, crystallizing in the monoclinic system. It has a Mohs hardness of 2.5-3, typically black, blue, gray or green in color, with a metallic luster, a specific gravity of 5.5-5.8. Its streak is black or blue.
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/c 1 |
| Cell (Å, °) | a = 15.246, b = 11.884, c = 13.494; α = 90, β = 116.35, γ = 90 |
| Cell volume | 2190.86 ų, Z = 48 |
| Axial ratios | 1.2829:1:1.1355calculated from COD 9008287 |
| Source structure | COD 9008287 (Zeitschrift fur Kristallographie, 1979) — 1 of 4 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 1.974 | 1.88 | 1.881 | 2.724 | 1.981 | 2.405 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 46.1 | 43.9 | 38.3 | 37 | 36.5 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9008287; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 5.79 g/cm³calculated from COD 9008287 |
|---|---|
| Hardness (Mohs) | 2.75single sourceWikidata (CC0) 2.5-3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 5.5-5.8 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, blue, gray, greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | black, blue, gray, greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | metallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 159.16 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Cu 79.85%, S 20.15% |
Classification
| Nickel-Strunz (10th) | 2.BA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.BA.05aWikidata (CC0) |
| Dana (8th) | 2.4.7.1Wikidata (CC0) |