A world-class fluorite from the Boltsburn Mine, England. This piece was found in the “great flat” sometime between its discovery in 1892 and the closing of the mine in 1931. These fluorites were mined to make special camera lenses and were used for submarine periscopes during World War 2. Fortunately, this example, escaped that fate.

The crystals are transparent and flawless. Despite its age and the specie’s fragility, it is free of any significant damage with only a few flea bites on tangential edges. In sunlight, the specimen radiates a beautiful shade of electric blue and purple, quintessential of English fluorites. The rich burgundy color stands out among the species with complex zoning and sharp corners.

The group weighs 7.75 pounds, and the large crystal measures over 6.5 inches along the lower edge. It came out of the Mineralogical Museum of Harvard University many years ago. It was illustrated in Mineral Collections of the American Northeast, the July-August 2016 supplement to The Mineralogical Record.