Chloritoid
Fe2+Al2O(SiO4)(OH)2IMA symbol: Cldgrandfathered
Chloritoid is a silicate mineral with the formula Fe2+Al2O(SiO4)(OH)2. It has a Mohs hardness of 6.5, typically black, gray, green or red in color, with a pearly luster, a specific gravity of 3.52-3.57. Its streak is colorless or gray; cleavage is imperfect.
Photos
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Crystallography
| Space group | C -1 |
|---|---|
| Cell (Å, °) | a = 9.467, b = 5.466, c = 9.14; α = 96.67, β = 101.04, γ = 90 |
| Cell volume | 460.949 ų, Z = 2 |
| Axial ratios | 1.7320:1:1.6722calculated from COD 9005442 |
| Source structure | COD 9005442 (European Journal of Mineralogy, 2000) — 1 of 4 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 4.454 | 2.441 | 2.45 | 2.408 | 1.831 | 1.823 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 27.7 | 22.4 | 22.1 | 14.1 | 12.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9005442; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.38 g/cm³calculated from COD 9005442 |
|---|---|
| Hardness (Mohs) | 6.5single sourceWikidata (CC0) 6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.52-3.57 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, gray, green, redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | colorless, gray, greenDana, System of Mineralogy, 6th ed. (1892) |
| Luster | pearlysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Cleavage | imperfectDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 9.AF.85Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.AF.85Wikidata (CC0) |
| Dana (8th) | 52.3.3.1Wikidata (CC0) |