Sterling Silver Whitby Jet Marcasite Double Marquise Necklace, P1306. This piece features a hand carved marquise shaped Whitby Jet gemstone, set inside a sterling silver frame. Above the Whitby Jet gemstone is a silver marquise shape accented with sparkling Marcasite stones through which an 18 inch silver chain passes at the top of the design.  All our Whitby Jet jewellery is designed and crafted within our very own workshops in Ashbourne, Derbyshire where a team of skilled craftsmen transform natural pieces of Whitby Jet into these stylish pieces of jewellery. You can find other matching Whitby Jet jewellery on our website. All articles purchased from C W Sellors are lovingly and securely dispatched with our elegant jewellery packaging. Dimensions 25mm x 10mm. Whitby Jet; 14mm x 7mm