Blue John Drop Kite Silver Earrings. E200. These elegant drop earrings boast a central diamond shaped piece of rare Blue John stone that has been sourced directly from Treak Cliff Cavern in Castleton. The stone is set in the centre of a sterling silver diamond mount which drops gracefully from the lobe with the classic post and butterfly fastenings. 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 jewellery. You can find other matching Blue John jewellery and other Blue John earrings on our website. Sterling Silver and Blue John.