Sterling Silver Whitby Jet Marcasite Dragonfly Brooch. M328. This gorgeous dragonfly brooch is hand made in Sterling Silver and features a beautifully hand carved Whitby Jet gemstone set in the body and sparkling Marcasite gemstones set in the wings and tail. This is an exquisite and detailed piece which would make a beautiful gift. The Whitby Jet stone has been directly sourced from the north east coast of Yorkhire. 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 stunning 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. Silver Whitby Jet Marcasite Dragonfly Brooch. 29mm x 29mm, Whitby Jet 7x5mm.