Most of the information in this article have been taken from:-
Bray, Warwick. The Gold of Eldorado. Royal Academy exhibition catalogue. 1978.
‘Gold is the most exquisite of all things...Whosoever possesses gold can acquire all that he desires in this world. Truly, for gold he can gain entrance for his soul into paradise.’ Columbus
The earliest evidence for metallurgy in the New World, dating from before 1500 BC, consists of bits of thin worked gold foil found in the hands of a man in a grave in the southern highlands of Peru. Nearby lay what was probably a tool-worker’s kit. The oldest extant elegant goldwork is of the Chavin style, dating from about 800 BC. In the ensuing centuries metalworking slowly spread, southward to northwest Argentina and northward to Colombia, toward the end of the last millennium BC, and to Central America in the early centuries AD. Although tools and weapons were made, metal was used principally for objects that symbolised supernatural power, and, by identification with this power, lordly status. Mythological motifs and beings were often depicted - intermediaries between man and the forces of nature.
Gold was an important trade item, and metal objects known by their style to have been made in one place have been found in quite distant sites, yet gold had little market value in itself; what was valued was the life-giving way it worked. Its symbolism was usually associated with the sun, hence with life and agricultural generation. It was important that metal imitated celestial light. Early sources tell us that the Inca thought of gold as ‘the sweat of the sun,’ and of silver as ‘the tears of the moon’.
The principal metals exploited in Colombia in pre-Hispanic times were gold and copper. Of these, gold was readily available, but the distribution of copper was more restricted. Two other metals, platinum, and silver, were of regional importance, though their use was limited. Platinum, from the rivers of Pacific Colombia and Ecuador, was employed by jewellers in the Tumaco region. Silver, which is found in most archaeological specimens in proportions of up to 25%, was not deliberately added, but was present naturally in the gold. Only in Nariño, which has strong technological links with Ecuador and Peru, did the Indians take a serious interest in silver as a metal in its own right. Since Colombia lacked tin, it was unable to develop a tradition of working bronze. Instead the favourite material was tumbaga (a gold-copper alloy with some accidental silver) which, under the names guanin gold or caricoli, was in use all round the Spanish Main at the time of the first European visits. ‘They work this gold, and have the custom of mixing it with copper and silver, and they adulterate it as much as they wish, and so it is of various purities and values.’ - Oviedo
In pre-Hispanic times, as at present, small-scale mining may have been a part-time occupation carried out during the dry season when stream beds were exposed. Some localities, however, supported specialist communities of full-time miners and smiths. The most renowned site of this kind was Buriticá, in the mountains of northern Antioquia. Buriticá was a true industrial centre, exploiting both alluvial and vein gold, and exchanging the surplus for food and other necessities and in the surrounding villages, the Conquistadors found workshops for melting down the metal, with crucibles, braziers and balances to weigh out the gold. The chronicles do not distinguish between the melting of bulk metal, and the melting of gold as a preliminary to making trinkets and jewellery, but the general impression is that Buriticá exported both finished items and raw metal to be worked up elsewhere. Some gold and jewellery was exported to the Quimbaya and Muisca peoples, but most of it was traded northwards to Dabeiba, where a community of specialist goldsmiths grew up on the basis of imported raw material. From Dabeiba, a trade route led to the Sinú and supplied the entire coastal region from Urabá to Cartagena. At places along the route were market centres where professional merchants exchanged coastal products (fish, salt, cotton cloth) for Sinú jewellery and ingots of raw metal from Antioquia.
Most of the gold used by the Indians was obtained using only the simplest equipment: fire-hardened digging sticks to break up the earth, and shallow wooden trays (bateas ) in which to carry and wash it. Spanish chronicles also note that streams were sometimes diverted to expose the gold-bearing gravels of their beds and that the Indians dug shafts to reach the gold-bearing quartz veins of the cordilleran regions of Caldas and Antioquia. The mines of Marmato (Caldas) are mentioned in sixteenth-century documents, and tools made of tumbaga were found there. During the nineteenth century, the British engineer Robert White visited Los Remedios in Antioquia (once the richest town of its size in the Indies), and discovered an extensive area of mine shafts, spaced some 3.5 to 4.5 metres apart, each shaft no more than one metre wide. White estimated that thousands of men could have been employed there, The deepest shafts had steps cut in the sides, and went down as much as 24 metres. The sloping shafts (inclined at about 30° ) were up to 36 metres in depth, and so narrow that a man could not turn round in them. Each shaft was a simple tunnel, with no side galleries and no attempt at shoring or ventilation.
Tumbaga offers several technical advantages. It is easier to cast than any of its constituent metals alone, and it reproduces fine decorative detail more accurately. The exact melting point depends on the composition, but the alloy of 20% copper and 80% gold melts at 911° compared with 1064° for pure gold and 1084° for copper. This alloy is harder than its individual constituents and metallographic examination has shown that chisels, axes and awls of tumbaga were cold-hammered until the working edges were almost as tough as those of bronze tools. Crucibles were clay - the goldsmiths of La Tolita in Ecuador, dispensed with crucibles altogether and melted their metal with the aid of a blowpipe in a hollow scraped in a charcoal slab. From incompletely fused specimens, it is clear that they also collected scrap metal for remelting. Blowpipes were essential as the Indians did not have the bellows. The result of the melting process is a tejuelo, a little button of metal with one face flattish and the other rounded, where it has followed the contour of the bottom of the crucible.
Hammering was used to stretch and planish the flat parts of certain cast pieces, to make simple discs, and as a technique for producing sheet metal. It is generally thought that hammering of sheet metal is a more primitive technique than casting but there is evidence that seems to show that both techniques were introduced simultaneously in Colombia and every one of the regional gold styles of Colombia includes both cast and hammered items. Hammers and cylindrical anvils were made of hard, fine-grained stone and were not hafted, but were held in the hand, the metal being worked by alternate hammering and annealing into sheet whose thinness and evenness compare well with today’s industrial product. Pure gold is soft and fairly easy to beat, but under continual hammering many of the alloys become ‘strain-hardened’, becoming brittle and liable to crack. Malleability can be restored by annealing - replacing the object in the furnace until the metal glows red, followed by quenching in water. Successful annealing requires skilled judgment and experience. With only the colour of the metal as a guide to temperature, the smith has to remove the object from the furnace at just the right moment; too much heating and the metal will begin to run; too little, and the process is ineffective.
For decorative effect, but also to give strength and rigidity to large objects of flimsy sheet, the metalsmiths pressed out repoussé design, working from the back, with the object resting on a bed of some yielding material, probably thick leather or a bag of sand. Such designs could be improved by working on the front of the piece, using a chasing tool to deepen the designs and to sharpen their edges, and additional freehand patterns were sometimes traced directly onto the metal. Raised designs were made by pressing and hammering the sheet metal over carved patterns.
Multi-piece ornaments, hollow figurines, lime-flasks, etc., were made by joining several previously shaped pieces of metal by hammer-welding, soldering, brazing, or by mechanical methods such as pinning, stapling, lacing with thin and pliable metal strip, or ‘clinching’ (in which the edges to be joined are overlapped, folded over, and then hammered down). Using similar methods, articles such as staffs, trumpets and conch shells were gilded with gold foil.
For very fine work, soldering becomes impracticable. The method used in Colombia and Ecuador, granulation, or diffusion bonding, was the one used in the ancient civilizations of the Old World and described by Pliny - although not rediscovered in Europe until seventy years ago. Using a copper compound (copper hydroxide or acetate) is mixed with an organic glue, and the mixture is used to stick the delicate elements into place. The complete object is then heated in the reducing atmosphere of a charcoal fire until the glue burns away and a natural gold-copper brazing alloy forms, resulting in the metallic bonding at the point of contact.The resultant join is barely perceptible. Casting in moulds was never common, although there is some evidence for its use. Even chisels and axes, which could have been easily produced in open moulds of stone or terracotta, seem to have been hammered and forged. Complicated shapes, both hollow and solid, were normally made using the lost-wax (or cire-perdue) method, in which the goldsmith modelled the object in wax and then encased it in clay, leaving a channel to the exterior. On heating, the melted was was poured out, and molten metal was poured in to replace it, leaving an exact copy of the wax original.
Hollow pieces required an interior core made from clay mixed with powdered charcoal, carved to the shape of the finished article and left to dry in the sun for two days (this to ensure the removal of all moisture to reduce the chances of an explosion during the casting stage).The smith next took molten beeswax, strained and purified it and rolled it out into a thin sheet which was laid over the core and pressed against it to follow the shape exactly. At this stage, any final appliqué or incised designs were added to the wax model and the pouring channel and air vents were added in the form of wax rods. The wax was brushed with a suspension of finely powdered charcoal in water or liquid clay and, after drying, the whole thing was enveloped in a thick casing of clay mixed with coarsely ground charcoal - porous enough to allow air and gases to escape during casting. The internal core was fixed in position by peg-like supports (chaplets) of green wood which passed through the wax leaving holes in the final casting. These holes would later be filled using molten metal. The complete assembled object was now heated in order to melt out the wax and to leave a space between the interior core and outer casing. While the mould was still hot (so that the metal would not set before flowing to all parts of the cast) molten gold was poured in to take the place of the wax. After cooling, the outer casing was broken open to extract the metal casting and the interior core material was removed. Because the outer casing has to be broken each time, every lost-wax casting is a unique creation.
Filigree is the soldering together of many fine wires, either to each other or to a backplate. False filigree imitates this effect but in fact the article is cast using the lost-wax method, many fine wax threads having been laid over the core.
Simple forms were occasionally covered with gold foil but generally the method used was ‘depletion gilding’ i.e. the removal of base metals at the surface of the object, leaving only the gold. On heating tumbaga in air, a layer of copper oxide forms on the surface of the object which can be removed with an acid solution made from the juice of certain plants, probably of the Oxalis family. Finally, the surfaces were cleaned and polished, not only to give a shiny finish, but also to consolidate and strengthen the superficial layer of gold on an object made of gilt tumbaga.Various cleaning and polishing agents were used. In Panama, the Indians used dried alligator dung, while in Tamalameque ‘they cleaned...with small quantities of fine sand that they brought in a maize husk, with their hands and water.’
Platinum occurs as little grey flakes or grains in the gold-bearing gravels of the rivers draining to the Pacific coast of Ecuador and Colombia. Since the platinum is found as specks of pure metal, and does not in nature alloy with the gold, the two metals can be separated mechanically by hand-washing and sorting. Some gold objects show tiny traces of platinum, present certainly because of poor sorting but other objects show platinum in proportions of between 26% and 72% i.e. as a deliberate additive. Platinum has such a high melting point (1775°) that native jewellers would never have been able to cast it pure, with the equipment available to them. Instead, it was mixed with a little gold dust and heated until the gold melted, binding the platinum particles together. This gold-with-platinum was alternately hammered and heated until it formed a compact mass which could be forged or cast like any normal alloy.
The first exploratory Spanish forays into South America were not always unfriendly ones - indeed they brought gifts of agricultural tools of iron, and also ‘many beads, many combs, knives and scissors, coloured hats, caps, and shirts finely worked at the neck’ to trade with the natives. But immediately they found gold and, fuelled by the story of ‘El Dorado’ (the Gilded One), started their quest for its pillage which was to last centuries. Expeditions crisscrossed the land and the gold was shipped back to Spain to be melted down for coin - coin that was to cause inflation for the whole of Europe and which was to lead to Spain’s relegation to a minor power. The chronicles of those expeditions described the gold producing areas of the time.
The Tairona region was flourishing and produced goldwork of a standard still admired by goldsmiths today. The Sinú was one of the richest and most populous areas of Colombia. More than 100,000 hectares of land were covered with a corduroy pattern of artificial ridges, providing well-drained fields for maize and root crops. Pedro de Heredia describes a temple big enough to hold more than a thousand people, and containing twenty-four wooden idols covered with sheet gold. Most of the raw material would have come from Buriticá and Dabeiba and the Spaniards noted that Sinú gold was of fine quality, containing some silver but little copper.
Radiocarbon dating shows that Muisca metalwork was nine hundred years old by the time the Spaniards reached Bogotá. The Spanish were enthusiastic in their descriptions of this fertile area situated in the high, temperate plateaux of Cundinamarca and Boyacá. The individual towns were organised into two loose federations, one in the north ruled by a chieftain with the title Zipa from Bogotá and the southern by another lord, the Zaque, from Hunsa. Not much remains of their presence because the houses were all built of wood.
The Quimbayas were a small tribe which lived, at the time of European contact, in the region of the modern municipios of Cartago and Pereira. They were farmers living in villages of wood-and-thatch huts, were rich in gold, worshipped idols made of wood or wax and had shamans who communicated with the gods. Typical Quimbaya gold pieces are often big and heavy, superbly finished and with a preference for large plain surfaces and restrained decoration. Both men and women are represented, modelled in the round, with plump bodies, small hands and feet and naked except for their jewellery.
The middle Magdalena Valley, the ancient Tolima region, was the home of two distinct Indian groups; in the north the Panches, bellicose headhunters and permanent enemies of the Muisca, and in the south, the Pijao, also warlike but skilled goldsmiths. Typical gold pieces are flat, stylised human figures terminating in crescent- shaped bases - traces of the Tolima style are evident in Popayán work.
The mountainous country around the headwaters of the Cauca and Magdalena rivers can be considered a single goldworking province. The three sub-regions of Popayán, San Agustín and Tierradentro are linked by the presence of monumental architecture, a unique tradition of stone sculpture, and by the occurrence of particular gold objects, notably the ‘Popayán eagle’. The main theme of San Agustín sculpture is a human or semi-human personage, sometimes partly transformed into a jaguar with bared fangs, or else with a jaguar-monster crouching over his back and head. This concept of a guardian spirit, simultaneously helper and protector, is widespread in Indian America today, where mythology and religion are also full of jaguar symbolism.
In the 1970’s, objects in a previously unknown style of gold work began to reach museums as a result of intensive treasure-hunting and tomb-robbing in highland Nariño, which, at the time of the Conquest, was the home of the Pastos and Quillacingas. The goldwork of the region has stylistic links with Ecuador and the central Andes, many pieces having a pale colour indicating an alloy with a good deal of silver. The finest objects are not three-dimensional castings, but are large items made from heavy sheet metal, burnished to a brilliant finish.
The Tumaco region formed a single cultural province, spilling over in to what is now Ecuador.
‘The people wear many gold studs in their faces. They pierce the flesh in many places, and in each hole they put a grain or stud of gold, and many of them put turquoises and fine emeralds.’ Francisco López de Gómara on Esmeraldas, 1552
When the coastal towns of Restrepo and Darién were founded in the twentieth century in what had been the Calima region, colonists clearing the forests uncovered traces of ancient occupation - rock carvings, house platforms, shaft tombs, ridged fields in the valley bottom and mosaics of little square fields on the slopes. The gold pieces found are masterpieces of hammering and casting. From sheet metal were made ear spools, nose ornaments, masks, lime-flasks and pectorals with human faces in high relief - all of them further decorated with repoussé designs and dangling elements. Characteristically, these items are large and made of relatively pure gold. In contrast, the finest cast pieces are miniatures - the pins or lime-dippers topped with birds, human figures and imaginary animals.