A spectacular array of artifacts made of native copper (an ore containing over 99.3% copper) has been found on sites near Pembroke, Ontario. Dating from the Middle Archaic Period (4,500 to 5,500 years ago), they include projectile points, knives, adzes, fish-hooks, awls, eyed needles, bracelets and pendants. The native copper was most likely obtained through trade with people living in the western Lake Superior region.
Native copper could be worked and shaped by hammering and pounding with stones. The brittle metal thus produced was heated in a fire to make it pliable.