Proustite
Ag3AsS3IMA symbol: Prsgrandfathered
Proustite is a sulfide or sulfosalt mineral with the formula Ag3AsS3, crystallizing in the trigonal system. It has a Mohs hardness of 2-2.5, typically red in color, with an adamantine luster, a specific gravity of 5.5-7.5. Its streak is red.
Photos
Crystallography
| Crystal system | trigonal crystal systemWikidata (CC0) |
|---|---|
| Space group | R 3 c :H |
| Cell (Å, °) | a = 10.825, b = 10.825, c = 8.704; α = 90, β = 90, γ = 120 |
| Cell volume | 883.294 ų, Z = 6 |
| Axial ratios | 1.0000:1:0.8041calculated from COD 9009993 |
| Source structure | COD 9009993 (Phase Transition, 1985) — 1 of 5 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.491 | 2.557 | 3.282 | 2.748 | 3.189 | 3.125 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 94.6 | 85.2 | 77.1 | 63.3 | 41.4 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009993; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 5.58 g/cm³calculated from COD 9009993 |
|---|---|
| Hardness (Mohs) | 2-2.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 5.5-7.5 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | vermilionsingle sourceWikidata (CC0) redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | adamantinesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 494.72 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Ag 65.41%, As 15.14%, S 19.44% |
Classification
| Nickel-Strunz (10th) | 2.GA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.GA.05Wikidata (CC0) |
| Dana (8th) | 3.4.1.1Wikidata (CC0) |