Bournonite (“cogwheel”-esque twins) Amethyst and these pieces are incredibly

and these pieces are incredibly difficult to find in good display specimens such as this

Specimen # BOL711B04

Specimen# CO712B191

which is not often found in well-crystallized display specimens

which I consider to be trivial

Bournonite (“cogwheel”-esque twins) Amethyst and these pieces are incrediblyA hard to find "cogwheel" esque group of sharp, fairly thick, blocky modified twinned crystals of Bournonite with excellent luster and aesthetics. The piece would be classified as a large thumbnail small toenail and displays well from several angles (my favorite being the last picture). The stacked appearance of the crystals, combined with the bright metallic luster, makes this one of the more unique smaller Bournonites I have handled from this mine.