BLUE JOHN - natural unpolished piece - Castleton, Derbyshire

'BLUE JOHN' FLUORITE

 Natural unpolished piece
 
Treak Cliff, Castleton, Derbyshire
 
A very deep purple piece of solid fluorite, with some crystals visible in cavities. Some banding is just visible but it is almost entirely opaque purple fluorite. It weighs almost a kilogram.

Blue John is only found in the vicinity of Treak Cliff, near Castleton in Derbyshire.  Blue John has been mined for hundreds of years and the banded pieces have been made into jewelry, bowls, goblets, vases, and numerous other decorative items that are now prized throughout the world.

The origin of the name Blue John is not clear.  It is likely that it was a local name given to the stone by the Derbyshire lead miners who already knew the zinc mineral sphalerite by the nickname ‘Black Jack’. 

Click on a picture for a larger image