Plancheite, Dioptase

This striking combination specimen from the Tantara Mine in the Democratic Republic of the Congo features powder-blue radial sprays of plancheite and emerald green dioptase. The label identifies the mineral as plancheite, though it could also be shattuckite, for which this locality is well known. In fact, some of the finest shattuckite specimens ever found have come from this mine. While plancheite is more commonly associated with dioptase (as seen here), whereas shattuckite is often found alongside malachite, from my understanding.

Much of the crystallization on this specimen is either massive or contacted, with one intact blue spherical formation resting on the remaining quartz matrix. The rest consists of attractive yet cleaved formations. Despite this, the specimen remains a fine, aesthetic, and representative example of old-stock material from this historic locality. The Tantara Mine has been completely abandoned and will likely never produce specimens again, pieces like this have become increasingly scarce. It's a wonderful miniature for collectors of rare secondary copper minerals from the Congo.

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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.