Fluorite

An ex-matrix, interpenetrant twinned crystal of Fluorite from the Hidden Forest Pocket at Diana Maria mine in Weardale, County Durham, England. One prism is a regular cube and its twin, an elongated cuboid, each measuring up to 3.6 cm and 3.3 cm respectively on their longest edges. In reflected light they are a deep, rich forest green and in transmitted light transform to vibrant chromium lime green with district colour zoning through yellow to almost colourless centres. The prisms have a bright glassy lustre and fluoresce deep purple to black. Under LWUV the entire specimen fluoresces intense lavender white.