Crichtonite, a Distinct Species

M. H. Hey, P. G. Embrey and E. E. Fejer
Department of Mineralogy, British Museum (Natural History), London, S.W. 7

Summary: Confusion over the status of crichtonite is due to the fact that de Bournon included two different minerals in his species: thin hexagonal plates are indeed ilmenite, as has been generally assumed, but the much rarer steep rhombohedra with basal plane are a separate species, with a distinctive X-ray powder pattern (three strongest lines: 3·39 Å,s; 2·875,s; 2·131,S) and a composition (Fe2+,Fe3+,Ti)1·71O3 with Fe2+:Fe3+:Ti near 8:7:33. There is a rhombohedral pseudo-cell containing three oxygens, with α 23° 19′, a 7·117 Å but there is some evidence of twinning, and the true symmetry is probably orthorhombic or lower.

Mineralogical Magazine; September 1969 v. 37; no. 287; p. 349-356; DOI: 10.1180/minmag.1969.037.287.06
© 1969, The Mineralogical Society
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