The Costume Jewelry Manufacturing Process Brass Brass is best described as a buttery yellow alloy of zinc and copper which has been manufactured for thousands of years all over the world. For jewelry, at least 67% copper and 33% zinc is used. Copper melts at 1083 Celsius and zinc boils at 907 Celsius and silver melts at 960 Celsius. Formulas with varying proportions of copper and zinc are alloyed together colors to achieve different variations of brass. ...