181363a0Nature1814605195802013633630028-0836195810.1038/181363a0ukNatureNatureNATUREnatureNature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public./nature/journal/v181/n4605issueJournal homeArchiveCurrent issueAdvance online publicationPrivacy policySubscribeNature Publishing GroupCurrent issue181363a0Coffinite in Cornwall
AU  - TAYLOR, K.
AU  - HARRISON, R. K.Atomic Energy Division, Geological Survey of Great Britain, Young Street, London, W.8. Nov. 5.COFFINITE, U(SiO4)1-x (OH)4x, a rare mineral previously reported only from the Colorado Plateau, United States1, and the Buller Gorge area of South Island, New Zealand2, has been identified in ore samples from Boskrow United Mine, Ponsanooth, Cornwall.Here coffinite occurs as a replacement of colloform pitchblende. All stages of replacement occur from incipient alteration along radial fractures and concentric growth bands to complete colloform pseudo-morphs measuring up to 5 mm. across.
Fig. 1. Colloform aggregates of coffinite (black, lower part of specimen) pseudomorphous after pitchblende, x 0 -85
The identification was based on X-ray powder photographs with the strongest lines at 3-49 (v.s.), 4-66 (s.), 2-64 (m.s.) and 1-80 (m.s.) A. A spectro-graphic analysis showed major uranium and silicon with vanadium and lanthanum among the minor elements.
A full description of the physical properties with a complete chemical analysis will be published elsewhere. The present communication is published by permission of the Director of the Geological Survey.Stieff, , L. R., Stern, , T. W., and Sherwood, , A. M., Amer. Min., 41, 675 (1956).ISIChemPortReed, , J. J., and Claridge, , G. G., Nature, 179, 546 (1957).ISIChemPort