Silver blue john domed oval ring r719 this stunning statement ring boasts a striking domed oval shaped cabochon of rare blue john stone that has been sourced directly from treak cliff cavern in castleton the stone is set within contemporarysterling silver and completed by 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 pieces of