Blue john oblong marcasite silver bracelet b878 this simple but stunning bracelet boasts a small oblong shaped piece of blue john stone that has been sourced directly from treak cliff cavern in castleton the blue john stone is set on a delicate sterling silver square linked chain that is embellished with exquisite marcasite stone for a sparkly finish all our blue john jewellery is designed and crafted within our very own workshops in ashbourne derbyshire where a team of skilled craftsmen tu