Halotrichite
Fe2+Al2(SO4)4·22H2OIMA symbol: Hthgrandfathered
Halotrichite is a sulfate mineral with the formula Fe2+Al2(SO4)4·22H2O, crystallizing in the monoclinic system. It has a Mohs hardness of 7.5, typically yellow in color, with a silky luster, a specific gravity of 1.885.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/c 1 |
| Cell (Å, °) | a = 6.1954, b = 24.262, c = 21.262; α = 90, β = 100.3, γ = 90 |
| Cell volume | 3144.45 ų, Z = 4 |
| Axial ratios | 0.2554:1:0.8763calculated from COD 9009974 |
| Source structure | COD 9009974 (Acta Geologica Hungarica, 1986) |
Powder X-ray diffraction (calculated)
| d (Å) | 4.803 | 15.843 | 3.498 | 3.503 | 4.3 | 6.046 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 39.6 | 39.4 | 32.6 | 28.1 | 26.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009974; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 1.787 g/cm³calculated from COD 9009974 |
|---|---|
| Hardness (Mohs) | 7.5single sourceDana's System, 3rd Appendix (1915) |
| Specific gravity | 1.885 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | yellowFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
| Luster | silkyFord, Dana's Textbook of Mineralogy, 3rd ed. (1922) |
Classification
| Nickel-Strunz (10th) | 7.CB.85Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 7.CB.85Wikidata (CC0) |
| Dana (8th) | 29.7.3.2Wikidata (CC0) |