18ct white gold blue john 077ct diamond cushion shaped ring r899 this enchanting ring boasts an unmissable cushion shaped piece of rare blue john stone in the centre that has been directly sourced from treak cliff cavern in castleton the stone is set within exquisite 18ct white gold and surrounded by mesmerising 077ct brilliant cut diamonds that run down the shoulders of the classic band all our blue john jewellery is designed and crafted within our very own workshops in ashbourne derbyshir