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Formula: PbBi4Te4S3
Sulphosalt, bismuth- and tellurium- bearing mineral
Crystal System: Trigonal
Specific gravity: 7.3724, 7.3738 and 7.3691 calculated for clogauite-12H, -24H and -36H, respectively, based on the
empirical formulae
Streak: Black
Magnetism: Non-magnetic
Environments
Clogauite is a new mineral, approved in 2023 and to date (October 2024) reported only from the type locality.
Localities
At the type locality, the Clogau St Davids Mine, Llanelltyd, Gwynedd, Wales, UK, clogauite type material is a
specimen representative of high-grade gold veins. Clogauite is the n = 1
member of the aleksite series,
PbnBi4Te4Sn+2, where n is the homologue number.
The type specimen contains lamellar intergrowths of clogauite, aleksite,
galena, tellurobismuthite
and minor chalcopyrite, with traces of
native gold. Many of the coarser lamellae in the specimen feature fine-scale,
partially disordered intergrowths of multiple lead -
bismuth -
chalcogenides of both the
aleksite series and the
tetradymite group minerals
tellurobismuthite and
tetradymite.
Clogauite occurs as fine lamellae, exceptionally up to 160 μm in width. Lustre, hardness, and other physical
properties could not be measured due to the small size of the sample, but they can be expected to closely resemble those
of tetradymite. Clogauite is non-magnetic and opaque
(MM 88.461–472).
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