Electrum

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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. This suggests that one reason for the invention of coinage in that area was to increase the profits from seignorage by issuing currency with a lower gold content than the commonly circulating metal.

Electrum was used as early as the third millennium BC in Old Kingdom Egypt, sometimes as an exterior coating to the pyramidions atop ancient Egyptian pyramids and obelisks.

Electrum was also used in the making of ancient drinking vessels and coins.

Electrum consists primarily of gold and silver but is sometimes found with traces of platinum, copper and other metals. As a result, electrum is a good conductor of electricity.

Analysis of the electrum composition in ancient Greek coinage dating from about 600 BC shows that the gold composition was about 55.5% in the coinage issued by Phocaea. In the early classical period, the gold composition of electrum ranged from 46% in Phokaia to 43% in Mytilene. In later coinage from these areas, dating to 326 BC, the gold composition averaged 40% to 41%. In the Hellenistic period electrum coins with a regularly decreasing proportion of gold were issued by the Carthaginians. In the later Roman (eastern Roman) empire controlled from Constantinople, the purity of the gold coinage was reduced, and an alloy that can be called electrum began to be used.

The colour of electrum is pale yellow or yellowish-white and the name is a Latinized form of the Greek word ἤλεκτρον (elektron) mentioned in the Odyssey meaning a metallic substance consisting of gold alloyed with silver. The same word was also used for the substance amber, probably because of the pale yellow color of certain varieties, and it is from the electrostatic properties of amber that the modern English words "electron" and "electricity" derive. Electrum was often referred to as white gold in ancient times but could be more accurately described as "pale gold". The modern use of the term white gold usually concerns gold alloyed with any one or a combination of nickel, silver, platinum and palladium to produce a silver-colored gold.

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.

• Tumbaga - a simillar material, originating in Pre-Columbian America; typically with a higher copper content and not necessarily containing significant amounts of silver
• Shakudō – a Japanese billon of gold and copper with a dark blue-purple patina
• Shibuichi
• Orichalcum – another distinct metal or alloy mentioned in texts from classical antiquity, later used to refer to brass
• Corinthian bronze – a highly-prized alloy in antiquity, which may have contained electrum
• Hepatizon
• Panchaloha
• Thokcha – an alloy of meteoric iron or "thunderbolt iron" commonly used in Tibet
• List of alloys

Wikimedia Commons has media related to Electrum.

• Electrum lion coins of the ancient Lydians (about 600BC)
• An image of the obverse of a Lydian coin made of electrum