Alloclasite
CoAsSIMA symbol: Aclgrandfathered
Alloclasite is a sulfide or sulfosalt mineral with the formula CoAsS, crystallizing in the monoclinic system. It has a Mohs hardness of 4-5, typically gray in color, a specific gravity of 6.6. Its streak is black; cleavage is perfect.
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21 1 |
| Cell (Å, °) | a = 4.661, b = 5.602, c = 3.411; α = 90, β = 90.2, γ = 90 |
| Cell volume | 89.064 ų, Z = 2 |
| Axial ratios | 0.8320:1:0.6089calculated from COD 9004112 |
| Source structure | COD 9004112 (The Canadian Mineralogist, 1976) |
Powder X-ray diffraction (calculated)
| d (Å) | 2.401 | 2.748 | 2.474 | 1.823 | 2.467 | 1.817 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 69.2 | 66.7 | 63.9 | 60.9 | 59.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9004112; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 6.187 g/cm³calculated from COD 9004112 |
|---|---|
| Hardness (Mohs) | 4-5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 6.6 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | blacksingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Cleavage | perfectsingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
Chemistry (calculated)
| Molecular weight | 165.92 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Co 35.52%, As 45.16%, S 19.33% |
Classification
| Nickel-Strunz (10th) | 2.EB.10bWikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.EB.10bWikidata (CC0) |