Silver Blue John Marcasite Marquise Ring. R746. This stunning ring boasts a marquise shaped cabochon of Blue John stone that has been sourced directly from Treak Cliff Cavern, Castleton. The stone is placed within an exquisite sterling silver setting embellished by dazzling marcasite stones, bringing a sophisticated sparkle to the piece. The ring is completed by a classic sterling silver band. 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 Blue John rings on our website. Silver Blue John Marcasite Marquise Ring