Blue john necklace oval silver nunq0000804rthis exquisite necklace boasts an unmissable cabochon oval shaped piece of rare blue john stone that has been sourced directly from treak cliff cavern in castleton the stone is placed within the centre of an oval sterling silver setting that hangs gracefully off a delicate bar style chainrall our blue john jewellery is designed and crafted within our very own workshops in ashbourne derbyshire where a team of skilled craftsmen turn the raw blue john