Rock 365 : Day 195 : Tetradymite
Day 195 : Tetradymite is a bismuth, tellurium sulphide. This sample
is from the St David’s Mine, Bontddu, Dolgellau, Gwynedd, Wales.
Cotton Collection, Keele.
Day 195 : Tetradymite is a bismuth, tellurium sulphide. This sample
is from the St David’s Mine, Bontddu, Dolgellau, Gwynedd, Wales.
Cotton Collection, Keele.
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