Earlier today I was reading about the apparent creator of coins, in about 625BC, king Alyattes of Lydia. They were made of electrum (a gold & silver alloy), of which Wikipedia reports "The weight of either precious metal could not just be weighed so they contained an imprint that identified the issuer who guaranteed the value of its contents".<p>Those were simpler times, I guess. Our far greater sophistication means we no longer need to bite or weigh or see an imprint on coins to test their true worth.