Sterling Silver Blue John Marcasite Rounded Edge Oval Necklace. P2118. This elegant necklace features a striking oval shaped cabochon of rare Blue John stone that has been sourced directly from Treak Cliff Cavern in Castleton. The stone is set within a sterling silver oval pendant embellished by glistening marcasite stones, giving the piece a sparkly and sophisticated finish. The pendant hangs gracefully from a fluid 18 inch sterling silver chain completed 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. Dimensions: Pendant 31x16mm including bale.