Tetradymite, Yecoraite

Tetradymite is a relatively uncommon bismuth-tellurium sulfosalt. This specimen features bright, steel-gray metallic tetradymite crystals set in what appears to be quartz matrix, sourced from the obscure San Martín de Porres Mine in Mexico. Adding to its mineralogical depth, scattered grains of yellow yecoraite—a rare calcium tellurite mineral of which this is the type locality—are present among the metallic tetradymite.

The San Martín de Porres Mine is a little-known quartz vein deposit that has yielded very few mineral specimens over the years. Located within a remote tellurium-rich region of Mexico, the mine has become notable among collectors for producing rare tellurium-bearing minerals, although specimens from the locality are virtually absent from the market and remain highly sought after. This piece stands out as a remarkable example of tellurium mineralization from one of Mexico’s lesser-known but mineralogically significant deposits.

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This specimen comes from the collection of Dr. Peter Tarassoff, a prominent figure in mineralogy, particularly known for his work at Mont Saint-Hilaire (MSH). His diligent collecting and examination efforts have led him to be the first to identify at least 35 species and discover 12 new species, not only at MSH but also at other alkaline localities. Dubbed the "Dean" of Mont Saint-Hilaire collectors, Peter was honoured with the naming of the new species petarasite in 1980. He has authored or co-authored numerous mineralogical articles and has been a member of the Mineralogical Association of Canada since 1964. Additionally, Peter has volunteered at the Redpath Museum for the past 21 years, where he was formally appointed the Honorary Curator of Mineralogy. In recognition of his significant contributions to mineralogy, Peter was awarded the 2017 Pinch Medal.