A cut and polished datolite half.The Mesnard Mine, located in Houghton County within Michigan's Keweenaw Peninsula, was organized in the 1860s following the discovery of a large mass of native copper near ancient mining pits. Historically, operations targeted the region's rich copper-bearing lodes, eventually becoming part of the broader Keweenaw mining boom that shaped the American copper industry. Geologically, the site sits within Precambrian basaltic lava flows and interbedded sedimentary rocks. Its mineralogy is famous for native copper, associated copper sulfides, and notable secondary minerals including porcelain-like datolite nodules found within the amygdaloidal zones.
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