Detailed information
Species
Bournonite, Freibergite
Dimensions
35 x 47 x 25
mm
Locality
Viboras Mine, Machacamarca Cornelio Saavedra Province Potosí Department, Bolivia
Condition
No recorded repairs
The Viboras mine at Machacamarca in the Potosí Department of Bolivia is most famous for its well-crystallised Bournonite. This small miniature features several excellent cog-wheel crystals and for added interest these are entwined with stalactitic rod-like overgrowths of the mineral Freibergite. It should be pointed out that Freibergite is now of a somewhat uncertain status and currently goes under the collective Freibergite Subgroup. The Bournonite crystals are developed up to 1.9 cm across and have a brilliant steel-grey metallic lustre. By contrast the micro-crystallised Freibergite tends to be a sooty matt black.