Bronze is an alloy of mostly copper and another element, usually tin, which has the effect of hardening and strengthening the metal. Bronze was one of the first alloys developed by humans, and it forms a gold-colored, brittle metal that was sometimes used to make early tools.
Bronze can be made with copper and elements other than tin. Sometimes academic papers treat various alloys of bronze as part of the same group as copper, zinc or brass and simply refer to them all as copper alloys. The most common mix of elements in bronze is 88 percent or more copper with 12 percent or less tin.