18ct White Gold 0.23ct Diamond Blue John Oval Stud Earrings, E1999. These classic stud earrings are designed with two stunning oval shaped pieces of rare Blue John stone at the centre, directly sourced from Castleton, Derbyshire. The 18ct white gold halo which glimmers around each stone, is set with a combined weight of 0.23cts of diamond. At C W Sellors, we have an expert team of gemstone and diamond specialists who handpick and grade each jewel to meet our high standards and a team of talented in house designers who combine their talents to bring you our exclusive Precious Gemstone collection. You can find other Blue John pieces online and in store to complement these earrings. All articles purchased from C W Sellors are lovingly and securely dispatched with our elegant jewellery packaging.