Sterling Silver Blue John Spiral Stud Earrings, E1913. This contemporary pair of earrings have been created using the finest quality, hand carved Blue John, sourced from Castleton in Derbyshire. The circular Blue John gemstone is surrounded by a swirling design of sterling slver, and would make a lovely gift, perfect for everyday wear. Secured with a post and butterfly back fastening. Dimensions: 9mm x 8mm, Blue John; 4mm x 4mm. All articles purchased from C W Sellors are lovingly and securely dispatched with our elegant jewellery packaging. Matching items are available within this collection.