Kyanite
Al2OSiO4IMA symbol: Kyapproved
Kyanite is a silicate mineral with the formula Al2OSiO4, crystallizing in the triclinic system. It has a Mohs hardness of 5-7.25, typically white, black, blue or gray in color, a specific gravity of 3.56-3.67. Its streak is red.
Photos
Crystallography
| Crystal system | triclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P -1 |
| Cell (Å, °) | a = 7.12, b = 7.8479, c = 5.5738; α = 89.974, β = 101.117, γ = 106 |
| Cell volume | 293.306 ų, Z = 4 |
| Axial ratios | 0.9072:1:0.7102calculated from COD 9001836 |
| Source structure | COD 9001836 (American Mineralogist, 1997) — 1 of 16 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.353 | 1.962 | 1.929 | 1.936 | 3.183 | 3.191 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 81.3 | 81.2 | 80.1 | 63.1 | 58.2 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9001836; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.67 g/cm³calculated from COD 9001836 |
|---|---|
| Hardness (Mohs) | 7.5single sourceWikidata (CC0) 4.5single sourceWikidata (CC0) 5-7.25single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.56-3.67 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, blue, gray, green, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 162.05 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Al 33.3%, O 49.37%, Si 17.33% |
Classification
| Nickel-Strunz (10th) | 9.AF.15Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.AF.15Wikidata (CC0) |
| Dana (8th) | 52.2.2c.1Wikidata (CC0) |