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Message:: [QUOTE="Valentinian, post: 3448346, member: 44316"]Be aware the numismatists use the term "bronze" differently than metallurgists. As a metal, bronze is an alloy of copper and tin. Modern bronze often has about 12% tin. In spite of the word "bronze" used to describe some ancient coins, ancient coins rarely have much tin. (Tin is close to white and the surface-silvering seen on third-century Roman coins was thought and said to be tin by 18th century numismatists until it was tested and found to actually be silver. Also, tin is found in Britain so British numismatists expected it in coins.)  Most studies of alloys study gold or silver coins, not AE. Cope found reduced AE folles of Constantine had 3-6% tin and each coin had as much or more lead than it did tin. Most coins that are not intended to be silver or gold are apparently intended to be either copper or "orichalcum", a golden-yellow alloy of copper and zinc which metallurgists would call brass (and was worth more than copper in the ratio of about 8 to 5). We can call them both "AE" and not have to know what alloy it is. It can be very difficult to tell the alloy of a 2000-year-old coin, especially if it is patinated, so by convention we can use "AE" for those indeterminate alloys that have very little silver or gold. The adjective "bronze" is (mis)used, but not because of modern science, rather because of tradition.[/QUOTE]