Original paper

Haydeeite, Cu3Mg(OH)6Cl2, a new mineral from the Haydee mine, Salar Grande, Atacama desert, Chile

Schlüter, Jochen; Malcherek, Thomas

Abstract

The new mineral haydeeite (IMA-CNMNC No. 2006-046) has the ideal chemical formula Cu3Mg(OH)6Cl2. It is trigonal with space group P3m1. Unit-cell data from single-crystal X-ray studies gave a = 6.2733(4), c = 5.7472(5) (Å), V = 195.88(2) Å3, Z = 1. Cell parameters refined from X-ray powder diffraction data are a = 6.2728(1), c = 5.7462(1) (Å), V = 195.81(1) Å3. Haydeeite is the Mg-dominant analogue of kapellasite (Cu3Zn(OH)6Cl2). The strongest reflections in the X-ray powder diffraction data, which show strong texture, are as follows dobs. (Å) (I, hkil): 5.745 (100, 0001), 2.872 (17, 0002), 1.915 (9, 0003), and 2.455 (6, 20-21). Haydeeite was found in the Haydee mine, which is located at the southern end of Salar Grande, Tarapacá Province, northern Chile. It occurs as greenish blue, vitreous, short prismatic, brittle crystals up to 1 mm in size with a perfect cleavage parallel to {0001}. The measured density is 3.27(1) g/cm3. The mineral is optically uniaxial negative with ω 1.753(5) and ε 1.710(5) and pleochroic with O = greenish blue and E = faint greenish blue. Haydeeite is closely associated with atacamite, gypsum, halite and occasionally covered by bassanite. Chemical analyses gave (wt.%) CuO 61.83, MgO 10.06, Cl 17.91, H2O 14.97, O ≡ Cl - 4.05, sum 100.72.The resulting empirical formula based on 8 anions is Cu2.95Mg0.95H6.30Cl1.92O6.08.The name is for the type locality, the Haydee copper mine.

Keywords

haydeeitenew mineralkapellasitechileatacamasalar grandehaydee minecopper magnesium hydroxihalogenide