Excellently formed Bournonite crystal clusters to 1.8 x 1.7cm. The Bournonite crystals display the classic cogwheel twinning habit, with a great metallic grey colour and luster. The Bournonite crystals are associated with bladed growths of translucent white Quartz, probably formed on or after preexisting Baryte crystals. A fine small cabinet specimen of Bournonite from the famous Herodsfoot Mine, Cornwall.