| 11. | Chalcopyrite is rarely found in association with native copper.
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| 12. | Other minerals noted within the ore bodies are willemite, sphalerite, chalcopyrite and rare native copper.
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| 13. | Halite stalactites and encrustations are also reported in the Quincy native copper mine of Hancock, Michigan.
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| 14. | Isle Royale in western Lake Superior was also a site of many tons of native copper.
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| 15. | It appears at this occurrence, dioptase is primary and has crystallized with quartz, native copper, and malachite.
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| 16. | Often, the nature of the gangue is important, as clay-rich native copper ores prove difficult to liberate.
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| 17. | The principal ore mineral was chalcocite, although native copper predominated in the lower part of the beds.
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| 18. | Polished native copper nugget from Keweenaw County.
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| 19. | The same deposits of native copper on the Keweenaw Peninsula and Isle Royale were later mined commercially.
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| 20. | The main ore exploited in those times was native copper from the oxidation zone of the deposit.
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