Pure Gold and Electrum

The most common form of free gold that is found in placer deposits and some lode deposits is in the form of a naturally occurring alloy of gold and silver called electrum. In nature gold can also be alloyed with arsenic, bismuth, copper and platinum group metals (PGM). There were so many PGM's associated with Peruvian gold that many years later many of the antique coins from Peru were melted down for their platinum content.

An Electrum Coin from Constantinople 

Naturally occurring electrum is the alloy of gold and silver is called electrum that can range from a bright golden yellow through various shades of gold where the color of gold becomes lighter and lighter until it finally becomes silver. In the jewelry trade this is called White Gold although most of it is man-made.

Electrum was the type of natural gold that was mined by the ancient Egyptians to the east of the Nile River from the desert between the river and the Red Sea. To the ancient Greeks it was known as gold or white gold that differentiated it from refined gold. The color of electrum can range anywhere from bright pale yellow to silver depending upon the amount of silver that is alloyed with the gold.

A nugget of electrum
Photo by Rob Lavinsky

A great deal of electrum is found in the ranges of Western Anatolia (Turkey) where the amount of gold can range from 70 to 90%. This type of electrum is in contrast to the electric that was used by the ancient Lydians that live in this area for coinage that ranged from 45 to 55% that is in approximately the same geographical area. This suggests that the coinage minted in Lydia were coins were invented was to increase the profits through artificially adding silver to gold so as to make more profit through the process of seignorage by issuing to the populace of Lydia a coin possessing a lower gold content that was found in the natural gold in the area.

The use of electrum goes all the way back to the third millennium BC during the days of the old Kingdom of Egypt or was often used as an exterior coating to the pyramidions that were atop the ancient Egyptian pyramids and obelisks.  They also used electrum for making ancient wine cups and in some places coins.