Blue john 4 stone dragonfly silver brooch m248 this striking brooch boasts four unmissable tear drop shaped pieces of cabochon blue john that has been directly sourced from treak cliff cavern in castleton the stone has then been set into this intricately crafted dragonfly design all 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 pieces of jewellery you c