Silver Blue John Marcasite Twisted Round Pendant Necklace. P2137. This petite romantic pendant boasts a highly polished Blue John stone sourced directly from the Treak Cliff Cavern in Castleton, Derbyshire. The stone is set at the heart of a sterling silver pendant which is embellished with a dazzling marcasite stones, giving the piece a sophisticated sparkle. The pendant hangs from a fluid 18 inch long sterling silver chain complete with 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. Silver Blue John Marcasite Twisted Round Pendant Necklace. Pendant 26x17mm including bale.