Bismuthinite with Chalcopyrite

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A stunning museum quality specimen of long acicular needles of the bismuth sulphide Bismuthinite which spans large voids in a vuggy skeletal framework of etched Milky Quartz. From Fowey Consols mine at Tywardreath, in the St. Austell District of Cornwall, England, the deeply striated metallic silver needles of Bismuthinite are commonly encrusted with sooty-black crystals of Cassiterite against a backdrop of massive, brassy-golden Chalcopyrite intermixed with the Quartz. In places where a cross-section of the Cassiterite coating can be studied (using a microscope), this crust is seen to have a radial form emanating from the c-axis of the Bismuthinite crystals, so forming a deposit of very finely crystallized tan-brown Cassiterite of the variety known as 'Wood Tin'. The Bismuthinite crystals attain around 2.7 cm in length and richly pervade the vugs in all parts of the specimen. A wonderful and mineralogically fascinating specimen of Bismuthinite and 'Wood Tin' from the classic Cornish locality of Fowey Consols.