Silver Whitby Jet Marcasite Large Heart Locket Necklace. P2149. This romantic, vintage style pendant boasts a highly polished heart shaped piece of the finest Whitby Jet stone that has been sourced directly from the north east coast of Yorkshire. The stone is set within the centre of a sterling silver heart locket that has been embellished with a dazzling marcasite stones, giving the piece a sophisticated sparkle. The locket hangs from an 18 inch long sterling silver chain complete with a classic bolt ring clasp for easy wear. 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 Large Heart Locket Necklace. Drop including bail 39mm, locket 26x26mm.