Ashoverite, a New Mineral, and Other Polymorphs of Zn(OH)2 from Milltown, Ashover, Derbyshire

A. M. Clark, E. E. Fejer, G. Cressey and P. C. Tandy
Department of Mineralogy, British Museum (Natural History), Cromwell Road, London SW7 5BD

Abstract: Four polymorphs of Zn(OH)2 have now been recorded from an oxidised vein exposure near Milltown, Ashover, Derbyshire; sweetite, wülfingite, γ-Zn(OH)2, and ashoverite. The last is a new mineral, a tetragonal modification of Zn(OH)2 containing minor quantities of Pb, Cd and Ca. Its unit cell dimensions are a 6.825(2) and c 33.36(4) Å, giving V = 1554 Å3; Z = 32; space group I41/amd, I41 md, or I4¯2d; Dmeas. 3.3, Dcalc 3.44 g cm−3. Ashoverite occurs as colourless platy crystals associated with fluorite; it is uniaxial positive with ω 1.629(2), ε 1.639(2). The chemical composition of sweetite is compared with that of ashoverite.

Keywords: ashoverite • new mineral • zinc hydroxide • sweetite • Milltown • Derbyshire

Mineralogical Magazine; December 1988 v. 52; no. 368; p. 699-702; DOI: 10.1180/minmag.1988.052.368.14
© 1988, The Mineralogical Society
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