Crookesite
Cu7TlSe4IMA symbol: Crkgrandfathered
Crookesite is a sulfide or sulfosalt mineral with the formula Cu7TlSe4, crystallizing in the tetragonal system. It has a Mohs hardness of 2.5-3, typically gray in color, with a metallic luster, a specific gravity of 6.9.
Photos
Crystallography
| Crystal system | tetragonal crystal systemWikidata (CC0) |
|---|---|
| Space group | I 4/m |
| Cell (Å, °) | a = 10.45, b = 10.45, c = 3.9708; α = 90, β = 90, γ = 90 |
| Cell volume | 433.621 ų, Z = 2 |
| Axial ratios | 1.0000:1:0.3800calculated from COD 9009757 |
| Source structure | COD 9009757 (Journal of Solid State Chemistry, 1991) — 1 of 3 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.026 | 2.136 | 3.305 | 2.619 | 1.849 | 1.792 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 82.6 | 79.2 | 78.3 | 69.3 | 58.2 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009757; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 7.391 g/cm³calculated from COD 9009757 |
|---|---|
| Hardness (Mohs) | 2.5-3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 6.9 g/cm3Dana, System of Mineralogy, 6th ed. (1892) |
| Color | graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | metallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 965.05 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Cu 46.09%, Tl 21.18%, Se 32.73% |
Classification
| Nickel-Strunz (10th) | 2.BD.50Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 2.BD.50Wikidata (CC0) |