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  • A superior native copper specimen featuring expansive sheet formation with distinctive patina coloration and contrasting dark shale matrix. The large specimen from White Pine Mine displays classic locality characteristics, excellent surface preservation, and represents significant material from this historic location.
  • A superior native copper specimen featuring expansive sheet formation with distinctive patina coloration and contrasting dark shale matrix. The large specimen from White Pine Mine displays classic locality characteristics, excellent surface preservation, and represents significant material from this historic location.

NATIVE COPPER

White Pine Mine, Ontonagon County, Michigan, USA
24 x 4.9 x 0.3 cm
$225.00
$225.00
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ABOUT THE SPECIMEN

Large and showy sheet of native copper with pieces of dark shale matrix still attached. This one stands out not only with its size, but also its color and form. All along the surface of the copper is a beautiful patina, made all the better with the added contrast of the shale atop. The White Pine Mine is no longer active, and this combination really showcases a growth that is characteristic for the locality.

 

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MORE INFO

White Pine is geologically distinct from the famous Keweenaw amygdaloid and conglomerate deposits to the northeast - it is a sediment-hosted stratiform deposit in which cupriferous brines migrated upward from the Copper Harbor Conglomerate red-bed aquifer into the overlying reduced silts and shales of the Nonesuch Formation at diagenetic temperatures below 130°C, with organic matter in the Nonesuch playing a direct role in copper precipitation. Native copper formed locally within basal ore horizons where sulfide had been fully incorporated into chalcocite, leaving copper-bearing fluids to precipitate metallic copper in intimate association with carbonaceous sediment. The resulting specimens look nothing like Keweenaw material; rather than crystallized masses, skulls, or half-breeds, White Pine copper typically occurs as thin, irregular sheet copper conforming to bedding planes, or as fine disseminations within dark gray-black shale matrix. The combination of metallic copper against carbonaceous sediment gives pieces a stark visual character with no real parallel elsewhere in Michigan collecting. Total production from closure in 1995 amounted to roughly four billion pounds of copper, yet specimen-quality sheet copper on shale matrix was always a byproduct of industrial extraction rather than targeted recovery, keeping fine examples genuinely uncommon in the market.