Copper (negative quartz casts) with Malachite

specimen number:
1791279

location:
Keweenaw Peninsula, Michigan, USA

description:
Choice crystallized grouping of native copper, this with a deep red cuprite patina. Malachite scattered throughout. The native copper crystals are forming negative casts after now gone quartz crystals. The specimen comes with an antique label from Michigan Tech University, the donor was L. L. Hubbard. The label is shown at the end of the video.

The copper mining history of the Keweenaw Peninsula and the broader Upper Peninsula of Michigan spans thousands of years, beginning with pre-Columbian indigenous mining and culminating in a massive industrial boom in the 19th and 20th centuries. Geologically, the region is defined by the Midcontinent Rift System, featuring a thick sequence of Keweenawan-age basaltic lava flows and interbedded sedimentary rocks. Unlike most global mining districts that extract copper oxides or sulfides, the central Keweenaw is globally unique for its vast deposits of exceptionally pure native copper housed within amygdaloidal basalt flows and conglomerates.

Lucius Lee Hubbard was an American geologist and mineralogist who served as the State Geologist of Michigan from 1893 to 1899. Geologically, his work focused heavily on the complex Precambrian copper-bearing formations, traps, and felsitic rocks of the Keweenaw Peninsula. Historically, after leading the state geological survey, he transitioned into industry management, serving as general manager for major copper mining operations like the Copper Range and Champion companies, and later contributing significantly to the academic governance of the Michigan College of Mines

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