Also, steel IS iron. Or rather an iron alloy.
By the time we got to making steel in mass lots, we were in the Industrial Age, and steel was only a small part of that.
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When I was young, books talked about a 'Copper Age', but ja as Gordius says, it's usually referred to as 'Chalcolithic' these days, as copper isn't strong enough to replace stone for tools for all purposes.