A polished piece of semi-precious Blue John from Castleton, Derbyshire, 11 by cm. Blue John is a variety of fluorite unique to the High Peak area.

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A polished piece of semi-precious Blue John from Castleton, Derbyshire. The piece is 11cm long and cm high. Blue John is a variety of fluorite uniquely found in the caves around Castleton in the High Peak district of Derbyshire, characterised by purplish-blue bands of colour. Anna Watson/Alamy

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Size: 5616px × 3744px
Photo credit: © Anna Watson / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: blue, castleton, crystal, derbyshire, district, fluorite, high, john, mined, mining, ornament, ornamental, peak, polished, purple, semi-precious, stone, yellow