Copper

$1,285.00

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418 sold last year · median $375.00 · last sale $15,000.00

Weinrich MineralsFeatured

113 for sale·206 sold

A beautifully crystallized grouping of native copper. In super condition. Nice patina on this one as well.Houghton County, Michigan, located on the Keweenaw Peninsula, is home to one of the most significant native copper deposits in the world. Geologically, the region features the Keweenawan Series, where ancient basaltic lava flows and interbedded conglomerates provided the structural voids necessary for hydrothermal fluids to deposit nearly pure native copper. Unlike most global deposits that require smelting of sulfide ores, the mining and quarrying operations here targeted large masses and fine grains of elemental copper hosted within the Portage Lake Volcanics. Historically, while indigenous peoples mined the area for millennia, industrial-scale production began in the mid-1840s and saw the rise of legendary operations like the Quincy and Calumet and Hecla mines. These industrial efforts reached their peak in the late 19th and early 20th centuries, providing a vast majority of the copper used for the early electrification of the United States. Significant mining activity continued through World War I, followed by a gradual decline as deeper reserves became more expensive to extract, with most major operations concluding by the late 1960s. Today, the district is recognized as a premier mineralogical locality and a critical site in American industrial history.