Archaeological excavations carried out in recent years show that although the Pre-Columbian cultures of Mexico, Central America and Peru were primarily 'stone-age', the various peoples - the Aztecs, Toltecs, Zapotecs, the Mayas and the Incas - possessed a fairly advanced knowledge of metalworking. In Mexico, where the Aztecs became the dominant power around the beginning of the 14th Century A.D., copper, tin and gold were worked as well as an alloy of copper and gold known as tumbaga.The techniques of smelting, casting, beating, soldering and gilding were understood and most of the output of the metalworkers, who were organized in separate guilds, appears to have been in the form of ornaments. Some utilitarian objects have survived and those in copper include fish-hooks, needles, pincers, mirror frames, small picks, chisels and axes. All the peoples of Mesoamerica possessed great skill as stone-masons and it is fairly probable that they used copper tubes with water and abrasives to drill blocks of stone. Prescott reported that the Inca masons of Peru used stone, copper and bronze tools. The latter were reserved for the more difficult tasks, and modern analysis has shown that the bronze used consisted of 94 per cent copper and 6 per cent tin. With the abundant supplies of both metals in this part of the world it is hardly surprising that the use of this alloy developed there.
One group of objects, which have been found in sites all over Mexico and Central America, are ornamental clapperless copper bells. These were in the form of a hollow shell with a pebble enclosed through a vertical slit to make a noise. They were decorated with geometric designs and were usually one or two inches long but several specimens up to six inches in length have been found.
The more primitive North-American Indians also used copper for tools, weapons, ornaments and amulets. The copper was probably native copper which was abundant around the shores of Lake Superior, and with the general increase in archaeological excavations in recent years, a number of valuable examples have been discovered - mainly in burial mounds. Some of the objects unearthed are believed to be about 5,000 years old (Fig. 9) and are attributed to the 'Old Copper Culture' which existed in the Great Lakes Region at that time.