Cacoxenite
Fe3+24AlO6(PO4)17(OH)12·75H2OIMA symbol: Cacgrandfathered
Cacoxenite is a phosphate, arsenate, or vanadate mineral with the formula Fe3+24AlO6(PO4)17(OH)12·75H2O, crystallizing in the hexagonal system. It has a Mohs hardness of 3-4, typically green in color, a specific gravity of 3. Its streak is white.
Photos
Crystallography
| Crystal system | hexagonal crystal systemWikidata (CC0) |
|---|---|
| Space group | P 63/m |
| Cell (Å, °) | a = 27.559, b = 27.559, c = 10.55; α = 90, β = 90, γ = 120 |
| Cell volume | 6939.21 ų, Z = 2 |
| Axial ratios | 1.0000:1:0.3828calculated from COD 9009221 |
| Source structure | COD 9009221 (Nature, 1983) — 1 of 2 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 11.933 | 13.78 | 6.856 | 4.86 | 9.649 | 9.021 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 18.3 | 17.8 | 14 | 12.8 | 12.2 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009221; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 1.707 g/cm³calculated from COD 9009221 |
|---|---|
| Hardness (Mohs) | 3-4single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) |
Classification
| Nickel-Strunz (10th) | 8.DC.40Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 8.DC.40Wikidata (CC0) |