Excerpt from: The Lure of Gold Introduction: Six Millennia of Gold The Copper, Bronze, and Iron Ages are established terms in human history--they refer concretely to the metals that were characteristic of the given historical period. By contrast, "golden ages" or "golden times" only ever truly existed in the imagination--as expectations or idealizing memories attached symbolically to a mythic metal that represented power, and to which magical significance and supernatural powers were attributed. The fascination that the yellow precious metal inspired has not diminished over millennia, and the symbolism associated with it has been the same across cultures and epochs: gold stands for the divine, the royal, the powerful, for the sun, light, and purity. Even as cultures have changed in response to economic, social, and intellectual revolutions, certain ideas have remained the same. The privilege that reserved gold above all for rulers, gods, and saints may have disappeared in the present, and it may have become a commodity available to all, but it has lost none of its timeless allure in the process. People today are attached not so much to the magic as to the beauty of the metal and its yellow gleam, which is why three-quarters of the world''s production of gold is used for jewelry to provide pleasure and display status. Gold is a rare, valuable metal, but the high regard in which it is held is not based on that alone. It is immortal in that it resists corrosion.

In human consciousness it has thus been associated with those other symbols of the permanent, the eternal, and the supernatural: the gods in early conceptions of spirituality and the beyond and the omnipotence of God in the monotheistic religions. For the god-kings of Egypt, gold was the flesh of the immortals. El Dorado, the gilded one, was the Colombian name for a ruler considered the equal of the sun, who was coated with mud and dusted with gold to make him the visible personification of the beliefs and ideas of his subjects. The apostate Israelites danced around Aaron''s golden calf. Every Bible concordance has a reference to the gold-covered columns of the temple that Solomon built. Gold was such a desirable, valuable gift that from the Middle Ages to the early modern period alchemists attempted to transform base metals into "pure" gold by means of mysterious, mystical operations. Gold became the symbol of the sun, silver of the moon. Tracing the noun "gold" and the adjective "golden" through literature could become a life''s work.

The metal has always had a place in language as the epitome of the beautiful, the noble, the unique. The curse of gold and the greed for it have also become proverbial. Virgil spoke of the "auri sacra fames," the sacred hunger for gold. Even an ancient author as sober and as concerned with facts as Pliny the Elder (AD 23-79) remarked in the thirty-third book of his Natural History, "O if only gold could be completely removed from life," which did not stop him from paying it respect as something special. The English political economist John Maynard Keynes (1883-1946) called gold a "barbarous" metal, and he was well aware that during the nineteenth century people from all countries streamed to the United States, Canada, and Australia in the hope of quick riches when they heard the news of sensational finds of gold. Jason and the Argonauts: A Myth of Gold''s Origins Until the early modern age, people had no idea how metal was formed or where it was most likely to be found. Diviners claimed to be able to search out both veins of water and metal deposits. Myths, sagas, and legends invoked the actions of the gods or mysterious powers to account for the existence of deposits.

Pliny mentions, among other tales, that the Scythians believed that griffins had brought gold from unknown distant lands. For the Greeks, the tale of the Argonauts was an allegory of divine intervention in the discovery and extraction of the noble metal. The hero Jason was given the task of finding the Golden Fleece, a ram''s fleece filled with gold glitter that lay in a gold-bearing stream and was guarded by a dragon. To help him accomplish this mission, the goddess Athena directed that the ship Argo, after which the Argonauts were named, be built and sailed to Colchis, a coastal area on the eastern Black Sea. There, the reigning king, Aetes, promised Jason the Golden Fleece on the condition that he perform several tasks first. The hero fulfilled them, with the help of Medea, Aetes'' daughter, but the untrustworthy king refused to hand over the Golden Fleece and instead tried to kill the Argonauts. Medea then put to sleep the dragon who guarded the fleece, so that Jason could seize it. He and the Argonauts quickly boarded their ship and sailed away.

The presence of gold in the sand of rivers, the associated tale of the Argonauts, and the extraction of gold glitter caught in the coats of animals long held a place in the human imagination, which is why Georgius Agricola (1494-1555) illustrated the Argonauts in his book De re metallica of 1556 (plate 14). Gold Deposits and Gold Mining Gold is in fact a widespread element in nature, though it is found only in limited concentrations. It makes up one part in five hundred mil-lion of the earth''s crust--silver is fifteen times and copper a million times more common. These statistics tell us little, however, because they do not take into account local deposits. Apart from seawater, which contains such extremely small traces of gold that it cannot be extracted economically--just thirty billionths of an ounce per gallon (0.02 mg per m3)--gold is accumulated in primary and secondary deposits on the land (plate 20). Primary deposits are solid stone or veins of ore that contain gold, whereas secondary deposits consist primarily of so-called placers, which result from the disintegration of gold-bearing stone and the deposition of the gold as sediment in water (plate 13). Placers can be either loose deposits (recent placers) or stable, geologically older formations (fossil placers).

Although it is usually found as dust, flakes, or grains, placer gold is occasionally found in larger clumps called nuggets (plate 16), which are very rare but can be quite large. In the nineteenth century a gold nugget supposedly weighing 2,975 pounds (1,350 kg) was found in the West Indies; it must have been about the size of a small chest of drawers. Australia has also boasted record nuggets of 193 pounds 6 ounces (87.74 kg) and 149 pounds 14 ounces (68 kg). Numerous rivers on all the continents have sometimes more, sometimes less gold. It can pay to mine placers with as little as 0.02 ounces of gold per ton of sand (0.5 g/MT).

The oldest method for extracting gold, washing, is based on gravity--that is, the specific gravity of gold, which, at around 19 grams (0.67 oz.) per cubic centimeter (0.061 in.3), is high in comparison to that of the materials with which it is found, like sand, which has a specific gravity of about 2.7 grams (0.095 oz.) per cubic centimeter.

Using everything from panning dishes and simple juice boxes to modern extracting equipment, gold has been separated out of promising areas from time immemorial in both small- and large-scale operations. Simple extraction methods--like those described and illustrated by Agricola (plate 15)--have hardly changed at all since the pre-modern and early modern periods. Even today, 20 to 25 percent of world gold production is based on simple methods of separation by gravity. The washing of river gravel and sand is practiced not only by amateur mineral hunters and collectors but also by professionals in Indonesia, Brazil, and other countries. Sometimes the yield is lucrative, which can lead to headline-producing gold rushes. Until the middle of the eighteenth century there was gold washing on many riverbanks, including the Rhine. Ducats of Rhine gold were minted for Elector Karl Theodor of the Palatinate, whose residence was in Mannheim (plate 17). Because placers are the product of the disintegration of primary de-posits, gold in solid stone has often been located by following the course of rivers and streams and constantly measuring how much placer gold their sediment contained.

An increase in the gold content of the placer was a sure sign that one was getting closer to gold-bearing rock formations. Primary deposits of gold can develop in various ways and can be found in a wide variety of stones of different geological ages. Gold in quartz veins, commonly known as hard-rock gold deposits, is particularly widespread (plates 18, 19). It is considerably more difficult to extract than placer gold, requiring both mining techniques and experience in underground excavation. That is also true, however, of hard, fossilized placers, which can be located at a considerable depth, as they are in South Africa. The gold particles have to be freed from the extracted hard ore by pounding and grinding. Mining gold ore requires planning and organization. It also requires the use of many trained laborers.

The exploitation of slaves and prisoners in gold mines has rightly been denounced, but even with forced labor efficient extraction was possible only when experienced foremen and expert miners supervised and took responsibility. Providing for so many people and supplying necessities like wood and water called for practiced logistics, so in antiquity the mining of hard-rock gold deposits on a large scale was undertaken only by empires that had that kind of organization, like Egypt and Rome. The purely mechanical separation of the valuable metal from the ac-companying stone was already being replaced in Roman times, according to Vitruvius (first century AD), by the process of amalgamation, in which the gold pa.