Copper
Unknown Owner
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Crystallized native copper throughout this breccia matrix.The Keweenaw Peninsula of Michigan is home to the largest concentration of native copper on Earth, situated within the Midcontinent Rift System. Geologically, the deposits formed approximately 1.1 billion years ago when basaltic lava flows and interbedded conglomerates were filled by copper-bearing hydrothermal fluids. This unique mineralization produced massive quantities of pure "native" metal rather than traditional copper oxides or sulfides. Historically, indigenous peoples mined the copper for thousands of years before the first modern American mining rush began in 1843. Major industrial operations, led by companies such as Calumet and Hecla, dominated the region throughout the late 19th and early 20th centuries. Production peaked during World War I, but as the mines reached extreme depths and costs increased, the industry steadily declined. Most major mines closed by the late 1960s, with the final large-scale operation, the White Pine Mine, shutting down its primary production in 1995.
Product details
SpeciesCopper
SizeLarge Cabinet
Dimensions18.0 x 10.0 x 7.0 cm
Added on04/17/2026
LocalityUSA, Michigan, Keweenaw Peninsula
Known provenance
| Date | Collector | Acquisition price |
|---|---|---|
| 04/2026 | Unknown Owner | $235.00 |
| — | Weinrich Minerals | Not disclosed |
Comments