Excellently formed classic Bournonite crystals measuring to 1.7 x 0.6cm are displayed to advantage on the specimen. Several Bournonite crystals on the specimen display the classic cogwheel twinning habit, having a great metallic grey colour and lustre. The Bournonite crystals are associated with translucent white Quartz. A fine small cabinet specimen of Bournonite from the famous Herodsfoot Mine, Cornwall.