Bournonite (''cogwheel'' twins)

Item Description

A beautiful Bournonite specimen from this well-known area in Peru featuring fine quality, silvery-grey, metallic crystals showing the classic "cogwheel"-twinning habit for which the species is known, measuring up to 9 mm which are associated with lustrous, silvery-brass colored, narrow prismatic crystals of Arsenopyrite and minor Quartz on matrix. A few spots of damage can be seen, so the piece is not 100% pristine, but still very showy and good quality for the locality. It's a rich specimen, loaded with Bournonite crystals, and displays nicely as you can see. Good Bournonites specimens from Pachapaqui are honestly fairly rare on the market these days, and this is one of the better pieces we've had to offer in the auctions recently.
Ex Brian Kosnar collection.