18ct White Gold Whitby Jet 0.25ct Diamond Oval Centre Ring. R1021. This elegant 18ct white gold ring features a hand carved Whitby Jet stone that has been sourced directly from the North East coast of Yorkshire. The highly polished stone is surrounded by 14 sparkling brilliant cut diamonds giving a total diamond weight of 0.25 carats. All our Whitby Jet jewellery is designed and crafted within our very own workshops in Derbyshire where a team of skilled craftsmen transform the natural Whitby Jet into these stunning pieces of jewellery. You can find other matching Whitby Jet jewellery and other Whitby Jet rings on our website. 18ct White Gold Whitby Jet 0.25ct Diamond Oval Centre Ring. Whitby Jet; 6.5mm x 5mm.