Fluorite    Treak Cliff Caverns, Casleton, Derbyshire, England.  Ex. Dr. Steve Chamberlain Collection.  This very rare example is from the Blue John fluorite occurrence known since Roman times. The fluorite is only really noted as carving material having been made into vases and other household goods of centuries. What is not so well-known is that on top of the massive fluorite seam are occasionally found plates of fluorite crystals! I have never seen these for sale and it appears to be because the miners simply ignore them. This example was found with two other exceptional piece by Dr. Chamberlain when he visited the occurrence in 1981. This is a fine reference piece.  There is minor damage to a couple crystal as can be seen, otherwise a specimen is in good condition. Some areas have a light overgrowths of an unknown brownish colored mineral. This specimen has a satin luster and the crystals are almost entirely opaque. The purple is uncommonly dark.  This group of crystals measures 5.3 x 4.5 x 3.1 cm.  Rare, rare, rare.  $100