Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. Its color ranges from pale to bright yellow, depending on the proportions of gold and silver. It has been produced artificially and is also known as "green gold".
Natural electrum "wires" on quartz, historic specimen from the old Smuggler-Union Mine, Telluride, Colorado, USA
The Pactolus river, from which Lydia obtained electrum for its early coinage
Electrum Phoenician bowl with mythological scenes, a sphinx frieze and the representation of a king vanquishing his enemies, Cypro-Archaic I, from Idalion, 8th–7th centuries BC (Louvre, Paris)
Brooch with a griffin protome, from the necropolis of Kameiros, Rhodes, c. 625–600 BC (Louvre)
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, opacity, and luster, but may have properties that differ from those of the pure metals, such as increased strength or hardness. In some cases, an alloy may reduce the overall cost of the material while preserving important properties. In other cases, the mixture imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength.
From left to right: three alloys (beryllium copper, Inconel, steel) and three pure metals (titanium, aluminum, magnesium)
Liquid bronze, being poured into molds during casting
A brass lamp
A gate valve, made from Inconel
