'Electrum' or 'white gold' the Greeks called the material of which the first coins were made. It consisted usually of three components: gold, silver and – as soon as the mixture was produced artificially – copper. The alloy of copper lowered the point of solidification of the molten metal. This meant that the gold smith had more time to cast the planchets and to strike the coins. Had he used pure gold or an alloy of pure gold and silver without copper, he would have had to work much faster. Moreover, electrum containing copper shows a higher brinell temper, meaning that coins containing copper are better protected from wear due to being passed from hand to hand.
We do not know exactly when craftsmen started to produce artificial electrum, but we suppose that this happened within the first half of the 6th century.