Copper
description: <p style="text-align: justify;">LOCALITY: Keweenaw Peninsula, Michigan, United States <br /><br />8" across, WEIGHT approximately 6 1/2" pounds <br /><br />This native copper specimen is only a decorator piece. It is only worth around US$2000 at retail because it it is a relatively large preserved Michigan native copper specimen. Far larger masses of crystallized native copper were excavated from the Michigan mines during America's first metal rush. Some of these masses weighed hundreds of kilograms or tons.  At most copper mines, native copper is a relatively rare mineral species confined to the oxidized zones of ore bodies that are normally polymetallic and may also be mined for other metals including silver, lead, zinc, gold, cobalt and uranium.  Another geological feature of many copper deposits is that most of the copper produced by these deposits is as the result of mining and processing copper containing sulfides including chalcopyrite, bornite, bournonite, chalcocite, covellite and cubanite; although this species does not exist at many copper mines, it is an ore mineral at the CSA Mine, near Cobar, New South Wales, Australia.  In contrast, the Michigan mines were much less diverse insofar as the mineral species that occurred in them.  The volume of oxidized ore that occurred at Keweenaw was negligable.  </p> <p style="text-align: justify;"> </p> <p style="text-align: justify;">Great Michigan native copper specimens that are around the size of this piece can easily be worth around US$500,000 or more at retail.  The pictured "decorator piece" is relatively inexpensive mainly because the copper crystals are not sharp and well defined.  Although the patina of this piece is original, it is more copper-brown instead of the more desired chocolate brown that collectors of Michigan native copper specimens crave.  The texture of the pictrured piece is smoothe and regular instead of appearing graining with pieces of embedded conglomerate.  </p> <p style="text-align: justify;"> </p> <p style="text-align: justify;">The main reason why this piece appears on this website is to help "new" collectors appreciate what an inexpensive Michigan native copper specimen looks like.  This is a good "coffee table rock."  It may also be suitable for a museum and especially if the museum's mineral gallery includes an exhibit that allows the public to touch or even heft one of the exhibited mineral specimens.  <br /><br />Photo by Matthew Webb of Melbourne, Victoria, Australia</p>

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