1. High-grade native copper made Ajo the first copper mine in Arizona. 2. The miners sometimes found masses of native copper up to hundreds of tons. 3. Michigan's native copper industry was essentially dead, after producing of copper. 4. The native copper deposits originate in fissures, steeply dipping conglomerate beds. 5. As native copper was available, ancient civilizations started to use it. 6. Associated minerals include chalcocite, atacamite, native copper , diopside, grossular and vesuvianite. 7. Masses of native copper weighing hundreds of tons were sometimes found in the mines. 8. The Cliff mined a fissure vein of native copper in Precambrian conglomerate and basalt beds. 9. The principal ore minerals were chalcocite and native copper . 10. Prior to the 19th century, Native American groups mined native copper on the Keweenaw Peninsula.
