Crookesite, Cu7TlSe4, from Littleham Cove, Devon: the first mineral containing essential thallium from the British Isles

The rare thallium copper selenide crookesite occurs as dark grey metallic needles in at least two cavities in a nodule collected from cliffs at Littleham Cove, Budleigh Salterton, Devon. This is the first report of a thallium mineral from the British Isles. The small crystal size, confusion in the mineralogical literature and the need to preserve as much of the specimen as possible for future study, made the identification particularly challenging. Thallium minerals have a very limited worldwide distribution. They are almost entirely restricted to unusual low temperature epithermal deposits. The discovery of crookesite in nodules in a Permian red bed environment is, therefore of significant interest. Thallium minerals do not appear to have been reported in this geological setting before.

Citation

Mike S. Rumsey, Ian Dossett, David I. Green, Jens Najorka and John Spratt (2015) Crookesite, Cu7TlSe4, from Littleham Cove, Devon: the first mineral containing essential thallium from the British Isles. Journal of The Russell Society, Vol. 18, pp. 48-52

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Type

Journal Article

Item Description

The Russell Society have made this journal freely available to increase the worldwide accessibility and usage of the papers published in the Journal.
NHM Repository

ISSN

0263-7839