18ct White Gold Blue John 0.25ct Brilliant Cut Diamond Oval Ring R900. This feminine ring features an oval cabochon of rare Blue John stone, directly sourced from Castleton, Derbyshire. The stone is set within highly polished 18 carat white gold and surrounded by 0.25cts of sparkling brilliant cut diamonds that run down the shoulders of the classic band. 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 this ring. All articles purchased from C W Sellors are lovingly and securely dispatched with our elegant jewellery packaging.