18ct White Gold Blue John Square 0.34 Carat Diamond Necklace. P1551C. This sophisticated necklace boasts a 0.86 carat square faceted piece of rare Blue John stone that has been sourced directly from Treak Cliff Cavern in Castleton. The stone is nestled within exquisite 18ct white gold that has been embellished by dazzling 0.34 carat diamonds for an eye catching finish. The pendant hangs gracefully from a white gold bail and chain that is fastened by a classic bolt ring clasp 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 necklaces on our website. 18ct White Gold Blue John Square 0.34 Carat Diamond Necklace