Blue john ring slim oblong silver r405 this simple and stylish ring boasts a stunning oblong shaped cabochon of the finest blue johnthat has been sourced directly from thetreak cliff cavern in castleton the stone is placed within an exquisite sterling silver setting that sits on a classic silver band all 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 stone into these stunning pi