Cornwallite
Cu5(AsO4)2(OH)4IMA symbol: Cnwgrandfathered
Cornwallite is a phosphate, arsenate, or vanadate mineral with the formula Cu5(AsO4)2(OH)4, crystallizing in the monoclinic system. It has a Mohs hardness of 4-5, typically green in color, a specific gravity of 4.16-4.17.
Photos
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Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P 1 21/c 1 |
| Cell (Å, °) | a = 4.6, b = 5.757, c = 17.38; α = 90, β = 91.87, γ = 90 |
| Cell volume | 460.016 ų, Z = 2 |
| Axial ratios | 0.7990:1:3.0189calculated from COD 9009405 |
| Source structure | COD 9009405 (Neues Jahrbuch fur Mineralogie, Monatshefte, 1999) |
Powder X-ray diffraction (calculated)
| d (Å) | 3.21 | 3.536 | 4.598 | 2.41 | 3.018 | 2.466 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 72 | 69.9 | 65.1 | 64 | 61.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009405; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.727 g/cm³calculated from COD 9009405 |
|---|---|
| Hardness (Mohs) | 4.5single sourceWikidata (CC0) 4-5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 4.16-4.17 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 663.6 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Cu 47.88%, As 22.58%, O 28.93%, H 0.61% |
Classification
| Nickel-Strunz (10th) | 8.BD.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 8.BD.05Wikidata (CC0) |