Silver Whitby Jet Marcasite Shield Ring. R819. This feminine Sterling Silver, Whitby Jet and Marcasite ring features a circular central piece of Whitby Jet that has been sourced directly from the north east coast of Yorkshire. The striking stone is surrounded by sparkling pieces of Marcasite set into a sterling silver shield and embellishing a classic silver band. 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 rings on our website. Silver Whitby Jet Marcasite Shield Ring. Whitby Jet 7mm diameter, top of ring 25mm diameter.