Scorodite
Fe3+(AsO4)·2H2OIMA symbol: Scdgrandfathered
Scorodite is a phosphate, arsenate, or vanadate mineral with the formula Fe3+(AsO4)·2H2O, crystallizing in the orthorhombic system. It has a Mohs hardness of 3.5-4, typically brown or green in color, with an adamantine or resinous luster, a specific gravity of 3.1-3.3. Its streak is white.
Photos
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Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P b c a |
| Cell (Å, °) | a = 8.942, b = 10.075, c = 10.339; α = 90, β = 90, γ = 90 |
| Cell volume | 931.4 ų, Z = 8 |
| Axial ratios | 0.8875:1:1.0262calculated from COD 2212542 |
| Source structure | COD 2212542 (Acta Crystallographica Section E, 2007) — 1 of 4 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 5.615 | 3.182 | 4.475 | 3.063 | 3.008 | 2.599 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 91.2 | 84.4 | 61.4 | 40.8 | 34.7 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 2212542; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.292 g/cm³calculated from COD 2212542 |
|---|---|
| Hardness (Mohs) | 3.5-4single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.1-3.3 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | brown, greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | adamantine, resinous, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 8.CD.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 8.CD.10Wikidata (CC0) |