Atacamite
Cu2Cl(OH)3IMA symbol: Atagrandfathered
Atacamite is a halide mineral with the formula Cu2Cl(OH)3, crystallizing in the orthorhombic system. It has a Mohs hardness of 3-3.5, typically black or green in color, with an adamantine or vitreous luster, a specific gravity of 3.75-3.77. Its streak is green.
Photos
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Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P n m a |
| Cell (Å, °) | a = 6.02797, b = 6.86383, c = 9.11562; α = 90, β = 90, γ = 90 |
| Cell volume | 377.158 ų, Z = 4 |
| Axial ratios | 0.8782:1:1.3281calculated from COD 9017806 |
| Source structure | COD 9017806 (Physical Review B - Condensed Matter, 2005) — 1 of 3 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 5.483 | 5.028 | 2.835 | 2.778 | 2.265 | 2.279 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 70.5 | 65.3 | 55.3 | 53.7 | 36.4 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9017806; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.761 g/cm³calculated from COD 9017806 |
|---|---|
| Hardness (Mohs) | 3-3.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.75-3.77 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | greensingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | adamantine, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 213.57 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Cu 59.51%, Cl 16.6%, O 22.47%, H 1.42% |
Classification
| Nickel-Strunz (10th) | 3.DA.10aWikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 3.DA.10aWikidata (CC0) |