This lovely pair of silver studs are a triangular shape and set with a Blue John stone. The size of the stones are 10mm x 10mm and are a lovely depth.
Blue John is a semi-precious mineral, a form of fluorite with bands of a purple-blue or yellowish colour. In the UK it is found only at Blue John Cavern and Treak Cliff Cavern at Castleton in Derbyshire. During the 19th century, it was mined for its ornamental value, and mining continues on a small scale.