Cyzicus

The first coins ever made were of a substance called electrum. Ancient Electrum Coinage of Cyzicus could be found occurring naturally along riversides in ancient times. Importantly, electrum contained gold and silver, with trace amounts of copper and other metals. It was bright and had such a white color to it that ancient Greeks who found it called it "white gold." Moreover, there were several types of electrum depending on the amount of gold and the different alloys it contained. Electrum could range in color from a bright white yellow a greenish tone. Adding Cadmium, which is highly toxic, to the gold turned it to a green color. The ancient Lydians who discovered this also realized the health concerns regarding its use.

Cyzicus Electrum Choice Very Fine Stater

An example