Electrum

Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. It has also been produced artificially. The ancient Greeks called it 'gold' or 'white gold', as opposed to 'refined gold'. Its color ranges from pale to bright yellow, depending on the proportions of gold and silver. The gold content of naturally occurring electrum in modern Western Anatolia ranges from 70% to 90%, in contrast to the 45–55% of electrum used in ancient Lydian coinage of the same geographical area.

History
Electrum is mentioned in an expedition sent by Pharaoh Sahure of the Fifth dynasty of Egypt (see Sahure). It is also discussed by Pliny the Elder in his Naturalis Historia.

Electrum is possibly referred to three times in the Bible (i.e. if the Septuagint's translation of the uncertain term חַשְׁמַל is accurate). In all three instances it is used to describe a type of glow seen in visions by the prophet Ezekiel (Ezekiel Ch.1 Vs.4 and 27;Ch. 8 Vs. 2). The word also appears in Sumerian texts; for instance, in the lost book, when Enki tells his master scribe (Edubsar) to write down all that he says, the text mentions a stylus of electrum with a crystal at the tip that glowed.[citation needed]

Electrum is believed to have been used in coins circa 600 BC in Lydia under the reign of Alyattes II.

Electrum was much better for coinage than gold, mostly because it was harder and more durable, but also because techniques for refining gold were not widespread at the time. The discrepancy between gold content of electrum from modern Western Anatolia (70–90%) and ancient Lydian coinage (45–55%) suggests that the Lydians had already solved the refining technology for silver and were adding refined silver to the local native electrum some decades before introducing the pure silver coins cited below.

In Lydia, electrum was minted into 4.7-gram coins, each valued at 1/3 stater (meaning "standard"). Three of these coins (with a weight of about 14.1 grams, almost half an ounce) totaled one stater, about one month's pay for a soldier. To complement the stater, fractions were made: the trite (third), the hekte (sixth), and so forth, including 1/24 of a stater, and even down to 1/48th and 1/96th of a stater. The 1/96 stater was only about 0.14 to 0.15 grams. Larger denominations, such as a one stater coin, were minted as well.

Because of variation in the composition of electrum, it was difficult to determine the exact worth of each coin. Widespread trading was hampered by this problem, as cautious foreign merchants offered poor rates on local electrum coin.

These difficulties were eliminated in 570 BC when pure silver coins were introduced. However, electrum currency remained common until approximately 350 BC. The simplest reason for this was that, because of the gold content, one 14.1 gram stater was worth as much as ten 14.1 gram silver pieces.

Conservation
See Gold