Sterling Silver Whitby Jet Marcasite Small Oval Necklace. P1316. This classic piece contains an oval hand carved Whitby Jet gemstone which is beautifully framed in sterling silver accented with round sparkling marcasite gemstones. This item is supplied complete with an 18 inch sterling silver chain. 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: Dimensions: 17mm x 9mm.