Arthurite
| Arthurite | |
|---|---|
| General | |
| Category | Arsenate minerals |
| Formula | CuFe23+[(OH,O)(AsO4,PO4,SO4)]2·4H2O |
| IMA symbol | Atu |
| Strunz classification | 8.DC.15 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/c |
| Unit cell | a = 10.189(2), b = 9.649(2) c = 5.598(1) [Å] β = 92.16(2)°; Z = 2 |
| Identification | |
| Color | Apple-green to bluish-green |
| Crystal habit | Acicular, prismatic, spherical |
| Mohs scale hardness | 3–4 |
| Luster | vitreous |
| Streak | not reported |
| Density | D(measured) = ~3.2 D(calculated) = 3.29 |
| Optical properties | Biaxial (+), may be biaxial (–) |
| Pleochroism | X = colorless to pale green; Y = gray-green; Z = olive-green |
| 2V angle | ~90° |
| Dispersion | r > v |
| Absorption spectra | Z > Y > X. α = 1.736 β = 1.767 γ = 1.796 |
| Other characteristics | Opacity: transparent to translucent |
Arthurite is a mineral composed of divalent copper and iron ions in combination with trivalent arsenate, phosphate and sulfate ions with hydrogen and oxygen. Initially discovered by Sir Arthur Russell in 1954 at Hingston Down Consols mine in Calstock, Cornwall, England, arthurite is formed as a resultant mineral in the oxidation region of some copper deposits by the variation of enargite or arsenopyrite. The chemical formula of Arthurite is CuFe23+(AsO4,PO4,SO4)2(O,OH)2·4H2O.
Arthurite is named after Arthur W. G. Kingsbury (1906–1968), a British mineralogist, and Sir Arthur Russell (1878–1964), a collector of minerals.