Bournonite is so often twinned or in classic "cogs-wheel" form that untwinned crystals are quite rare. This Quiruvilca (Peru) specimen is that unusual sort, here are many Bournonite crystals, some over 1.2 cm but no twins. In fine condition overall most crystals are perfect but with good magnification some small areas of rough edges are found. For this notoriously fragile specie that is impressive. Some bright golden pyrite adds contrast to the dark silver-metallic Bournonite. For some reason the Pyrite at Quiruvilca Mine is often especially bright and lustrous, it seems to be more stable than most and keeps the bright golden color much better than any other Pyrite I know. A fine addition to a serious Sulfide collection.