Bournonite (“cogwheels”) black A rare and UN-repaired Tourmaline

A rare and UN-repaired Tourmaline example from this beloved locality in California

which is typically what you would expect out of a metamorphic contact like this

Specimen# CO712B131

Considering the millions of tons of tin ore that Bolivia has yielded

this would make a nice addition to any thumbnail suite

Bournonite (“cogwheels”) black A rare and UN-repaired TourmalineA hard to find "cogwheel" group of sharp, thick, blocky modified twinned crystals of Bournonite with excellent metallic luster. The piece displays well from a few angles. The stacked appearance of the crystals, combined with the bright luster, makes this one of the more eye catching smaller Bournonites available. Specimen # BOL711B23