Copper with Tenorite

specimen number:
8701006

location:
Phoenix Mine, Keweenaw Co., Michigan, USA

description:
Superb crystallized native copper specimen with a lustrous black tenorite patina. In super condition, this is a competition quality miniature specimen from this Michigan classic.

The Phoenix Mine, located in Keweenaw County, Michigan, is one of the earliest and most historically significant native copper operations on the Keweenaw Peninsula. Geologically, the mine exploited the Phoenix fissure and the Ashbed amygdaloidal lode, where hydrothermal fluids deposited pure copper within the vesicular basalt and conglomerate layers of the Midcontinent Rift System. This locality is renowned for producing exceptionally sharp and well-formed crystallized copper, which frequently displays a characteristic dark, dull, or soot-black patina of tenorite, a copper oxide that provides a striking aesthetic contrast to the underlying metal. Historically, mining and quarrying activities at the site began as early as 1844 under the Lake Superior Copper Company, making it one of the first organized mining ventures in the district. The mine underwent several reorganizations and periods of closure, with its most productive years occurring between 1850 and 1886, followed by a final attempt at large-scale production by the Phoenix Consolidated Copper Company from 1899 to 1905. Despite its relatively modest total copper output compared to the massive Calumet and Hecla operations, the Phoenix Mine remains legendary for its contribution to early American mining history and for the distinct character of its tenorite-coated copper crystals.

Questions about this specimen?
Send an email or call us: 314-341-1811.