Sterling Silver Blue John 10mm Round Stud Earrings. E099. These classic 10mm stud earrings are part of our handmade Heritage collection and boast two striking cabochon of Blue John stone that have been sourced directly from Treak Cliff Cavern in Castleton. The stones are framed within classic Sterling Silver settings and are completed by simple post and butterfly fastenings for easy wear. 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 rings online and in-store.