Silver Whitby Jet Marcasite Open Circle Pendant Necklace. P2142. This feminine pendant features a round cabochon of Whitby Jet stone, sourced directly from the North East coast of Yorkshire. The stone is framed by and exquisite sterling silver setting that showcases dazzling marcasite, giving the piece a sophisticated sparkle. The pendant hangs gracefully from a fluid 18 inch long silver chain complete with a classic bolt ring clasp. All our Whitby Jet jewellery is designed and crafted within our very own workshops in Derbyshire where a team of skilled craftsmen turn the raw Jet into these stunning pieces of jewellery. You can find other matching Whitby Jet jewellery and other Whitby Jet necklaces on our website. Silver Whitby Jet Marcasite Open Circle Pendant Necklace. Sterling Silver 18 inch chain, Pendant 32mm, Stone 10mm.