Polydymite
Ni2+Ni3+2S4IMA symbol: Pldgrandfathered
Polydymite is a sulfide or sulfosalt mineral with the formula Ni2+Ni3+2S4, crystallizing in the cubic system. It has a Mohs hardness of 3, typically brown or red in color, with a metallic luster, a specific gravity of 4.54-4.81. Its streak is black or gray.
Photos
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Crystallography
| Crystal system | cubic crystal systemWikidata (CC0) |
|---|---|
| Space group | F d -3 m :1 |
| Cell (Å, °) | a = 9.457, b = 9.457, c = 9.457; α = 90, β = 90, γ = 90 |
| Cell volume | 845.785 ų, Z = 8 |
| Axial ratios | 1.0000:1:1.0000calculated from COD 9009863 |
| Source structure | COD 9009863 (Arkiv for Mineralogi och Geologi, 1947) |
Powder X-ray diffraction (calculated)
| d (Å) | 2.851 | 1.672 | 1.82 | 2.364 | 3.344 | 1.231 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 81.2 | 46.6 | 46.4 | 30.4 | 16.7 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009863; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.78 g/cm³calculated from COD 9009863 |
|---|---|
| Hardness (Mohs) | 3single sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Specific gravity | 4.54-4.81 g/cm3corroboratedFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Color | brown, redsingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Streak | black, graysingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Luster | metallicsingle sourceFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
Classification
| Nickel-Strunz (10th) | 2.DA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.DA.05Wikidata (CC0) |
| Dana (8th) | 2.10.1.7Wikidata (CC0) |