About six thousand year ago man lived in what we call the Stone Age. This is because he made most of his tools and weapons out of stone. He had not yet learned how to use metals.
Probably the first metals man learned how to use were copper and gold. The reason is that these metals occur in nature in a free state as well as in ores. Man found nuggets of copper and gold and was able to hammer them into various shapes without having to melt them. We don’t know the date when men discovered how to use these metals, but we do know that copper was used as long ago as 6000 B.C. Gold was first used some time before 4000 B.C. By about 3000 B.C man had learned some of the most important things about using metals. By this time the metals silver and lead had been discovered, but copper was the one used most since it was the strongest and most plentiful. Man first learned to beat metal into useful shapes, such as bowls, tools and weapons.
Once he began using metals, he discovered the processes of annealing (making a metal soft and tough by heating and then slowly coaling it), melting, carting and smelting. Also, he could get copper from its ore, which was more plentiful than the nuggets. Later man discovered tin and learned to mix copper and tin, which made bronze. From about 3500 B.C to about 1200 B.C bronze was the most important material for making tools and weapons. This period is called the Bronze Age. Man knew about iron from meteorites he found, long before he discovered how to work iron, and this knowledge spread all over the world. Iron replaced bronze for most users. This was the beginning of the Iron Age.
By the time of the Romans, seven metals were known: gold, copper, silver, lead, tin, iron and mercury.
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