9ct yellow gold blue john dinky stud earrings e279 a classic cushion shaped pair of stud earrings solidly backed with 9ct gold and set with hand polished blue john which is sourced directly from the treak cliff cavern in castleton derbyshire attached to a post and butterfly fitting these earrings are neat and discreet 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 in