Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper
and other metals. It has also been produced artificially, and is often known as green
gold. The ancient Greeks called it 'gold' or 'white gold', as opposed to 'refined gold'.
Its colour 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 seigniorage by issuing currency with a lower gold content
than the commonly circulating metal. Electrum was used for the earliest metal coins,
and 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. For several decades the medals awarded with
the Nobel Prize have been made of gold-plated green gold.
The name electrum was also used to denote German silver, mainly for its use in making
technical instruments.
Composition Electrum consists primarily of gold and silver
but is sometimes found with traces of platinum, copper, and other metals. The name is mostly
applied informally to compositions between about 20-80% gold and 20-80% silver atoms,
but these are strictly called gold or silver depending on the dominant element. Analysis
of the composition of electrum in ancient Greek coinage dating from about 600 BC shows
that the gold content was about 55.5% in the coinage issued by Phocaea. In the early classical
period, the gold content of electrum ranged from 46% in Phokaia to 43% in Mytilene. In
later coinage from these areas, dating to 326 BC, the gold content 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 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. Appearance
The colour of electrum is pale yellow or yellowish-white and the name is a Latinized form of the Greek
word ἤλεκτρον, mentioned in the Odyssey referring to a metallic substance consisting
of gold alloyed with silver. The same word was also used for the substance amber, likely
because of the pale yellow colour of certain varieties, and it is from amber's electrostatic
properties that the modern English words "electron" and "electricity" are derived. 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-coloured
gold. History
Electrum is mentioned in an account of an expedition sent by Pharaoh Sahure of the Fifth
dynasty of Egypt. It is also discussed by Pliny the Elder in his Naturalis Historia.
Electrum is possibly referred to three times in the Bible. In all three instances it is
used to describe a type of glow seen in visions by the prophet Ezekiel.
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 and ancient Lydian coinage 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. Three of
these coins totaled one stater, about one month's pay for a soldier. To complement the
stater, fractions were made: the trite, the hekte, 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. See also
Tumbaga - a similar 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 - another Japanese alloy known for its patina;
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.
References ^ Discussion about the use of terms 'Electrum',
'German silver' and 'Nickel silver' for drawing instruments
External links Electrum lion coins of the ancient Lydians
An image of the obverse of a Lydian coin made of electrum