Sterling Silver Blue John Heart Spiral Stud Earrings, E1912. This contemporary pair of earrings have been created using the finest quality, hand carved Blue John, sourced from Castleton in Derbyshire. The circular piece of Blue John is surrounded by a spiral design of sterling silver, and would make a lovely gift, perfect for everyday wear. Dimensions: 10mm x 11mm, 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.