Glaucophane
܆Na2(Mg3Al2)Si8O22(OH)2IMA symbol: Glnredefined
Glaucophane is a silicate mineral with the formula ܆Na2(Mg3Al2)Si8O22(OH)2, crystallizing in the monoclinic system. It has a Mohs hardness of 6-6.5, typically black, blue or gray in color, with a pearly or vitreous luster, a specific gravity of 3.103-3.113. Its streak is blue or gray.
Photos
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C 1 2/m 1 |
| Cell (Å, °) | a = 9.531, b = 17.759, c = 5.303; α = 90, β = 103.59, γ = 90 |
| Cell volume | 872.461 ų, Z = 2 |
| Axial ratios | 0.5367:1:0.2986calculated from COD 9005070 |
| Source structure | COD 9005070 (European Journal of Mineralogy, 1991) — 1 of 4 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 8.214 | 2.688 | 3.042 | 2.517 | 4.44 | 3.377 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 80.5 | 57.6 | 41.3 | 26.6 | 24.7 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9005070; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.148 g/cm³calculated from COD 9005070 |
|---|---|
| Hardness (Mohs) | 6-6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.103-3.113 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, blue, graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | blue, graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 9.DE.25Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.DE.25Wikidata (CC0) |
| Dana (8th) | 66.1.3c.1Wikidata (CC0) |