Enargite
Cu3AsS4IMA symbol: Enggrandfathered
Enargite is a sulfide or sulfosalt mineral with the formula Cu3AsS4, crystallizing in the orthorhombic system. It has a Mohs hardness of 3, typically black or gray in color, with a metallic luster, a specific gravity of 4.43-4.45. Its streak is black or gray; cleavage is none.
Photos
Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P m n 21 |
| Cell (Å, °) | a = 7.399, b = 6.428, c = 6.145; α = 90, β = 90, γ = 90 |
| Cell volume | 292.261 ų, Z = 2 |
| Axial ratios | 1.1511:1:0.9560calculated from COD 9014599 |
| Source structure | COD 9014599 (Zeitschrift fur Kristallographie, 2004) — 1 of 7 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.843 | 3.206 | 3.072 | 1.726 | 1.854 | 2.848 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 83.1 | 79.3 | 67.7 | 62 | 46.3 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9014599; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.475 g/cm³calculated from COD 9014599 |
|---|---|
| Hardness (Mohs) | 3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 4.43-4.45 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | blacksingle sourceWikidata (CC0) black, graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | metallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Cleavage | nonesingle sourceDana's System, 2nd Appendix (1909) |
Chemistry (calculated)
| Molecular weight | 393.82 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Cu 48.41%, As 19.02%, S 32.57% |
Classification
| Nickel-Strunz (10th) | 2.KA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.KA.05Wikidata (CC0) |
| Dana (8th) | 3.2.1.1Wikidata (CC0) |