Digenite with Malachite, Azurite

specimen number:
2062061

location:
Flambeau Mine, Rusk Co., Wisconsin, USA

description:
Rich massive digenite hosting open pocket slide with crystalline azurite and malachite. Neat locality example for the species.

The Flambeau Mine near Ladysmith in Rusk County, Wisconsin, was a copper and gold mine that operated as an open pit from 1993 to 1997. The deposit was a volcanogenic massive sulfide ore body hosted in Precambrian volcanic rocks of the Penokean region. Mining produced copper rich ore containing minerals such as chalcopyrite, pyrite, and sphalerite, along with small amounts of gold and silver. Although the mine operated for only a few years, it became known among collectors for producing well crystallized specimens of sulfide minerals from pockets encountered during mining.

Digenite is a copper sulfide mineral with the chemical formula Cu9S5 that forms in copper rich ore deposits. It commonly develops in the secondary enrichment zones of copper deposits where it forms through alteration of other copper sulfide minerals such as chalcopyrite and bornite. Digenite typically appears as dark blue to black massive material or fine grained aggregates rather than well formed crystals. It is often associated with minerals such as chalcocite, covellite, and bornite in copper ore bodies.

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