gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1979.043.325.04 Georgeite, a New Amorphous Copper Carbonate from the Carr Boyd Mine, Western Australia Bridge P. J. Government Chemical Laboratories, 30 Plain Street, Perth, Western Australia 6000 Just J. Australian Selection (Pty.) Ltd., 50 St. George's Terrace, Perth, Western Australia 6000 Hey M. H. Department of Geology and Mineralogy, Parks Road, Oxford 3 1979 43 325 97 98 4 1 1978 25 9 1978 Copyright © 1979, The Mineralogical Society 1979 Summary

Georgeite, an amorphous copper carbonatehydrate, has been found in the oxidation zone of the Carr Boyd nickel deposit, Western Australia. It forms thin coatings mostly associated with malachite and chalconatronite on partly weathered tremolite rock containing disseminated copper and iron sulphides.

Physical properties: Colour light blue, streak pale blue, lustre vitreous to earthy, fracture conchoidal, soft, sp. gr. 2.55; transparent to sub-opaque (aggregates), n(NaD) = 1.593, isotropic. Amorphous to X-rays and electron beam.

Chemical microanalysis gave (wt%) CuO 54.9, ZnO 0.4, Na2O 2.7, CO2 20.8, H2O 21.7, sum 100.5. After deduction of all Na2O and corresponding amounts of CuO, CO2, and H2O as chalconatronite (12.35 wt%) the atomic ratios correspond to an empirical formula (Cu5.0, Zn0.05)(CO3)3(OH)4.12.6.3H2O, the ideal formula being Cu5(CO3)3(OH)4.6H2O.