Blue john necklace pear drop twist marcasite silver n893rthis mesmerising necklace boasts an unmissable cabochon tear drop shaped piece of rare blue john stone that has been directly sourced from treak cliff cavern in castleton the stone has been set in the centre of an intricately crafted sterling silver design that runs up the chain of the piece the setting has been embellished by glistening marcasite stones giving a sparkly and sophisticated finish to the piecerall our blue john jewelle