gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1984.048.347.12 Sweetite, a New Mineral from Derbyshire Clark A. M. Fejer E. E. Couper A. G. Jones G. C. Department of Mineralogy, British Museum (Natural History), Cromwell Road, London SW7 5BD 6 1984 48 347 267 269 4 10 1983 Copyright © 1984, The Mineralogical Society 1984 Abstract

Sweetite, naturally occurring Zn(OH)2 with tetragonal symmetry, has been found at Milltown, near Ashover, Derbyshire. It occurs as colourless or whitish bipyramids up to 1 mm in size scattered over the surface of colourless fluorite cubes. The cell dimensions are α 8,222 and c 14.34Å with Z = 20. The strongest lines of the X-ray powder pattern are (d, I, hkl): 4.53 37 (112); 3.572 60 (004,202,211); 2.922 100 (213,220); 2.708 18 (105,204); 2.257 17 (224,215,321); 1.840 11 (226,420,413); 1.764 24 (316). Sweetite is uniaxial negative, ω 1.635, ɛ 1.628. Dmeas is close to 3.33 and Dcale 3.41. Chemical analysis gave 84.3% ZnO and 17.0% H2O, while theoretical figures for Zn(OH)2 are 81.9 and 18.1% respectively.