Quartz from Blackdene Mine, Ireshopeburn, England, UK

Blackdene mine, close to the village of Ireshopeburn in Weardale, County Durham, England, is known for its purple Fluorite, but it did produce other colours and this is a fine example of yellow. A long, narrow cleaved plate of Fluorite displays top faces of intergrown, large honey-yellow Fluorite crystals, the largest measuring 6 cm across its widest edge. The Fluorite is heavily coated with stubby clear Quartz crystals of dazzling lustre, preferentially coating the Fluorite crystals from one direction. Under LWUV the Fluorite fluoresces a bright, rich purple, especially across the whole of its base. Where the Fluorite in overgrown by Quartz crystals, these shield the Fluorite and so these areas are non-fluorescent.