Blue john brooch oval brooch silver m011rthis simple but unmissable brooch boasts a stunning oval shaped cabochon blue john stone that has been sourced directly from treak cliff cavern in castleton the stone has been set within a sterling silver base with an exquisite twisted detailing around the edgerall our blue john jewellery is designed and crafted within our very own workshops in ashbourne derbyshire where a team of skilled craftsmen turn the raw blue john stone into these stunning pie