Copper

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A large mass of native copper, this collected in August, 2000 diving offshore and 35 feet of water. Great Sand Bay, located along the northern shore of Michigan's Keweenaw Peninsula between Eagle River and Eagle Harbor, is a scenic coastal area with a rich geological and recreational history. Geologically, the site features a combination of Jacobsville Sandstone and conglomerate beds of the Copper Harbor Formation, interspersed with erosion-resistant lava flows known as the Lake Shore Traps. Mineralogically, the area is famous among rockhounds and collectors for yielding native copper masses, Lake Superior agates, and quartz, with offshore hydrothermal veins occasionally producing exceptional specimen pockets. Historically, while industrial mining focused heavily on the interior ridges of the Keweenaw copper boom during the 19th and 20th centuries, Great Sand Bay gained lasting renown among modern historians and mineral enthusiasts for underwater copper discoveries, including massive float copper specimens like the famous Lake Copper.

Product details

SpeciesCopper

SizeCabinet

Dimensions14.5 x 9.0 x 2.5 cm

Added on08/11/2026

LocalityUSA, Michigan, Great Sand Bay

Current owner

Unknown Owner

Previous owners

Date	Collector	Acquisition price
—	Weinrich Minerals	Not disclosed

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Mineral guide

Learn about Copper

native copper with spinel-twinned crystals and arborescences; notable from Lake Superior, Itauz, Dongchuan, Corocoro, prized for color and localities.

Regional guide