Silver Blue John Marcasite Fancy Pear Necklace. P2979. This stunning pendant features a pear shaped hand carved Blue John gemstone set at the heart of a double Sterling Silver and Marcasite frame. A very eye catching pendant with a vintage feel, this piece uses only the finest Blue John stone which has been source directly from Treak Cliff Cavern in Castleton. The pendant hangs beautifully from a fluid 18" silver chain. 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 online and instore. Silver Blue John Marcasite Fancy Pear Necklace. 45mm x 25mm, Blue John; 13mm x 9mm.