By David Bressan
Because it doesn’t corrode over time, gold has been a symbol of everlasting power and wealth since antiquity. According to legend, the use of gold as currency was introduced by King Croesus in the 6th century B.C. The oldest real coins made from electrum – a naturally occurring alloy of gold and silver – date into the 7th century B.C. and were discovered in the ancient city of Ephesus (modern Turkey).
From there the use of gold as currency was imported by the Greeks to the Roman empire, where the coins were called “aureo.” The name derives from the Latin “aurum,” meaning dawn, referring to the golden-yellow shimmer of the metal. The English term gold derives from the Indo-Euroepan word “ghel,” which also means yellow. For this peculiar property of gold, (besides copper, it’s the only metal with a distinct color) it was associated with the sun in many ancient cultures.
Today gold still plays an important role in our culture. Even during the Olympic games, the winners respectively get gold, silver and bronze medals. Though in reality even the gold-medal is composed of a core of silver-copper alloy covered by at least 6 grams of gold, the symbolic value of the gold outshines its low economic value.
Gold is a surprisingly common metal, found in traces in almost all rocks, dissolved in water and even in life-forms. However its concentration is very low, making extraction labor-intensive. Concentrations of 4-10 gram per ton of rock are considered exploitable. Most gold is recovered from mines, found in its native form or in in combination with sulfur-minerals associated with quartz veins.