18ct Yellow Gold Blue John Diamond Oval Ring. R1110. This unique 18ct yellow gold ring features a stunning hand carved cabochon of the finest Blue John stone which has been sourced directly from Castleton, Derbyshire. 0.22cts of luxurious sparkling diamonds frame the highly polished Blue John and adorn the shoulders of the ring. The perfect engagement ring featuring a rare British gemstone.  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 matching Blue John and diamond pieces online and in store. All articles purchased from C W Sellors are lovingly and securely dispatched with our elegant jewellery packaging.