Very Large Blue-Green Fluorite Rogerley Mine, Frosterley, Weardale, North...

weardale region fluorites frosterley located mining geology north historically known mentioned forster’s characteristic mineral specimens rogerley district northern greenbank mike sutcliff early 1970s presently britain worked commercially purpose recovering crystallized strata westgarth forster descriptions regional stratigraphy generally years specimen twice size examples occasionally seen today’s market— displays huge sharp intact cubic crystals outstanding bluish-green england lindsay published document accepted approximately measuring locality deep large blue-green fluorite pennines durham discovered 1821 book today pocket length luster color