A cheap, silvery-grey metal commonly used for coins when a government looks to make a near worthless coin after politicians have been bribed by the zinc industry. Such coins in fountains begin corroding in 48 hours, fouling the water. The U.S. cent�s alloy remained 95% copper and 5% zinc until 1982, when the composition was changed to 97.5% zinc and 2.5% copper, really copper-plated zinc. Zinc was usually alloyed with copper to make brass and certain types of bronze. Zinc can be melted with copper in a covered crucible. The zinc gas flows out a pipe in the top, and cools to become pure metallic zinc. This was discovered in India in the early 1400s and spread from there to China. Brass was introduced to Europe from China and Europeans had no idea how it was produced. In the 1400s China changed its coins from bronze to brass because zinc was much cheaper than tin. When trace amounts of zinc turn up in ancient objects, because of some fluke in production. So the presence of more than 1% zinc in a claimed ancient object shows that it is not genuine.
Source: Numiscadero Spanish to English Glossary (Gary Beals)