Blue John – Oval Cabochon Cut

Description

Blue John – Oval Cabochon Cut 7.40 Carats.  14.1 x 10.3  mm

Blue John is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish color. In the UK it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire.