Bournonite ("cogwheels")

Viboras Section, Machacamarca Mine, near Colavi, Potosi Department, Bolivia
Small Cabinet, 9.3 x 6.8 x 4.0 cm
Start Time: 10/11/2018 6:45:00 pm (CDT)
End Time: 10/18/2018 6:45:00 pm (CDT)
Auction Closed

Item Description

One of the few "cogwheel" specimens of Bournonite that I have offered from Bolivia in the auctions for a while. This piece features an attractive, sharp, metallic, lustrous, silvery-grey color, "cogwheel"-shaped crystal group measuring aesthetically sitting on Pyrite octahedra which are coated by either Sphalerite or Bornite on matrix. The largest section of the "cogwheel" measures 3.2 x 2.4 cm across, but there are "stringers" the cover a good portion of the display side. The vast majority of the Bournonite group is undamaged, only a few minor imperfections. This specimen is from a find in 2008 in Bolivia. This one is much better than the majority I've handled from Machacamarca. The Bolivian Bournonite "cogwheels" are some of the finest examples of the material to come out in 50+ years, and they compare well with their contemporary Chinese counterparts. A piece like this from Machacamarca is very difficult to find, so I hold it in high regard in terms of value, around $1,500 retail.

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