Fluorite (daylight fluorescence), 50 Year Pocket, Rogerley Mine, Weardale, County Durham, England

Certainly one of the most famous contemporary fluorite localities in the world is the Rogerley Mine near Frosterley, England. The mine, one of the first in the world to mine exclusively for mineral specimens, produces very attractive and unique fluorite. Emerald-green fluorite from the mine, like this one, have remarkable fluorescent properties. When exposed to long wave ultraviolet light the fluorite turns a neon blue reminiscent of night club lights. However the best surprise is when you place the specimen into daylight and watch the green suddenly turn a deep purple-blue hue - truly amazing! I once took my personal specimen to my daughter's school to show for her grade 3 science class. The teacher's wanted to know my magic trick as I pulled the specimen in and out of bright sunlight coming in the window, but I said the secret can only be learned in physics class! This piece exhibits all of these colour phenomena and displays interpenetrate twins with sharp cubic faces too. This very nice example is from the famous "50 Year Pocket" discovery named after the mine's 50th anniversary. From: Rogerley Mine, Weardale, County Durham, England. Dimensions: 6 cm x 10 cm