Chalcocyanite

Chalcocyanite CuSO4

c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Orthorhombic. Point Group: 2/m 2/m 2/m. Crystals are tabular on {010} and slightly elongated along [001], to several mm; typically in crystalline incrustations. Physical Properties: Hardness = 3.5 D(meas.) = 3.65(5) D(calc.) = 3.89 Soluble in H2O; very hygroscopic, altering to chalcanthite. Optical Properties: Transparent to translucent. Color: Pale green, pale brown, pale yellow, sky-blue; colorless in transmitted light. Optical Class: Biaxial (–). Orientation: X = b; Y = a; Z = c. Dispersion: r > v, extreme. α = 1.724(3) β = 1.733(3) γ = 1.739(3) 2V(meas.) = Large. Cell Data: Space Group: P nmb. a = 6.709(1) b = 8.409(1) c = 4.833(1) Z = 4 X-ray Powder Pattern: Synthetic. 3.549 (100), 2.62 (95b), 4.187 (75), 2.42 (50b), 1.775 (30), 1.433 (20), 1.430 (18) Chemistry: (1) (2) SO3 50.30 50.16 CuO 49.47 49.84 Total 99.77 100.00 (1) Vesuvius, Italy. (2) CuSO4. Occurrence: As sublimates near volcanic fumaroles. Association: Dolerophanite, melanothallite, eriochalcite, euchlorine (Vesuvius, Italy); euchlorine, eriochalcite, dolerophanite, melanothallite, piypite, ponomarevite, cotunnite, sofiite, fedotovite, tenorite (Tolbachik volcano, Russia); stoiberite, shcherbinaite, ziesite, bannermanite, chalcanthite (Izalco volcano, El Salvador). Distribution: From Mount Vesuvius, Campania, Italy. At the Tolbachik fissure volcano, Kamchatka Peninsula, Russia. On Izalco volcano, El Salvador. Name: From the Greek for copper and azure-blue, in allusion to the composition and color change caused by hydration. References: (1) Palache, C., H. Berman, and C. Frondel (1951) Dana’s system of mineralogy, (7th edition), v. II, 429–430. (2) Wildner, M. and G. Giester (1988) Crystal structure refinements of synthetic chalcocyanite (CuSO4) and zincosite (ZnSO4). Mineral. Petrol., 39, 201–209. (3) (1964) NBS Mono. 25, 3, 29.