Silver Blue John Marcasite Marquise Beaded Edge Ring. R749. This stunning ring is part of our Marcasite handmade jewellery collection and boasts a striking marquise shaped cabochon of the finest Blue John, which has been sourced directly from the Treak Cliff Cavern, Castleton in Derbyshire, framed by glittering Marcasite stones. The stone is placed within an exquisite Sterling Silver beaded detail setting and is completed with a classic sterling silver band. All our Blue John jewellery is designed and crafted within our very own workshops in Derbyshire where a team of skilled craftsmen turn the raw Blue John into these stunning pieces of jewellery. You can find other matching Blue John jewellery and other Blue John rings online and instore. Silver Blue John Marcasite Marquise Beaded Edge Ring. 19mmx11mm.