From the determination of trace amounts of platinum in tumbaga alloys, we turn to the discovery of major amounts of platinum as a component in a Recuay Fox and Crown, dated from approximately the 1st century AD to the 5th century AD, shown in Figures 15, 16, 17, and 18.

This piece is an impressive example of ancient South American goldworking and can be ascribed to the Recuay cultural area, located in the area of Callejon de Huaylas and the headwaters of the Rio Santa. The Recuay style is characterized by vibrant artistic designs, and is known primarily from collections of fine ceramics vessels generally made in a white kaolinite paste. It is reminiscent of the Moche style in technical mastery and iconography. Serpents, felines and condors are common motifs. Very little metalwork is known from the Recuay cultural areea and few pieces have been adequately published.

The Recuay crown examined here is a very fine example of ancient goldworking. The crown itself consists of a band of gold alloy about 5.5 cm high and about 0.2mm thick. The band is made in hammered sheet which has been ornamented with a cut-out design showing small human faces in a repeating pattern, with the eyes, nose and mouth of the face shown by cut-out areas. From microscopic examination it can be seen that this design has been cut using a chisel. The pattern is repeated so that the small faces appear upside clown on the top of the band, in a design executed with great skill. Pairs of small holes at the top and bottom of this crown probably indicate where attachments of small dangles were affixed. The design on the crown is rather similar to textile patterns from the Paracas-Nazca cultural regions. The method of construction is essentially the same as the techniques used to construct Moche metalwork, with most of the joins between pieces of metal being made mechanically. The crown itself is made in a native gold alloy, with no platinum content that could be detected by x-ray fluorescence analysis. This band has an unusual matte appearance with some staining which is difficult to characterize, possibly due to some oxidation of the silver content, but this is hard to prove without destructive sampling, which was not undertaken on the band.

The head, which has a serpent-like quality, is of a fox and has been attached to the band with tour tabs passing through slots cut into the crown. The head of the fox is made of two pieces of gold which are joined together by a technique which is distinctively pre-Hispanic: the two rounded gold strips are cut with tabs and the tabs are then overlapped and hammer welded to join the strips together, thus reinforcing the join between the two pieces and making good use of the hammer welding potentialities of gold alloys.

The head has two raised elliptical rims for the inset eyes, which appear to be of turquoise. The ears are carefully made with a subtle rim of gold on the edge of the ears, hammered back to thicken the edge and make a smooth line to the shape of the ear. The mouth of the animal head is fixed to the head with tour staples, three on one sheet of gold on the top of the mouth and one underneath. This mouth is made in a number of components: the two major pieces are shaped into a curve for the upper and lower parts and these are closed at the top and bottom inside of the mouth to form two solid shapes. A strip of gold sheet has been attached to the comer of the mouth at each side to complete the jaw.

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Figure 16 : Partial view of Recuay fox. The anthropomorphic design of part of the headband or crown can just be seen with the animal head attached showing part of the upper view of the figure. Small staples that attach the jaw to the head through the gold sheet of the jaw can be clearly seen.

Copper alloy whiskers have been applied to the top mouth part by pushing small holes through the gold sheet and attaching small round hammered copper wires, most of which are now very heavily corroded and lost. The mouth itself is completed with tour gold alloy parts representing teeth on the top and bottom jaw, held in place with three small tabs which slot into the sheets forming the floor and roof of the mouth. Two copper alloy fangs are attached to the jaws at the front and a serpent-like gold tongue protrudes between the fangs. All of these components appear to be original to the piece and there is no evidence for the recent attachment of any foreign elements.

An analysis of the object was carried out using X-ray fluorescence analysis. A major and unexpected surprise was the discovery that the serrated teeth are made in a gold-platinum with minor components of silver and copper. These serrated teeth components are silvery in colour and without analysis would be mistaken for a silver or silver-copper alloy. In order to investigate the composition and structure of these serrated teeth, a tiny sample was taken from a folded over edge and mounted for metallographic examination. The resulting polished section is shown in Figure 18, after etching in aqua regia to reveal the platinum grains. The microstructure reveals a heavily worked matrix in which extensive dissolution of the platinum laths has occurred, resulting in a very well dispersed scatter of platinum particles. The successful dispersion of the remnant platinum grains, and the dissolution of some of the platinum into the gold matrix, is responsible for the silvery colour of the resulting alloy: not all gold-platinum composites will produce a silvery colour: there is a whole range of possibilities from dull golden to silver-gold and silver coloured, often with a grey-silver aspect or steel-grey patination. This is because of the iron content of the native platinum grains of South America, which usually contain between 1% - 4% of iron, giving rise to possible interference colours on tarnishing or thin films of iron oxide from oxidation.

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Figure 17 : Another view of Recuay animal head showing some of detail of the jaw with protruding gold alloy for the tongue, platinum gold alloy inset teeth, represented by serrated components in the upper and lower jaw. The copper alloy fangs in the mouth can be seen an the slight reddish hue under the corrosion reveals parts of cinnabar painted surface as confirmed by powder X-ray diffraction.

There is a strong resemblance between the microstructure of this gold-platinum alloy sheet and those from the La Tolita-Tumaco cultural area, crossing the Ecuadorian-Colombian border. Platinum could not be molten by the pre-Columbian Indians, and was sintered with gold, producing the World's first powder metallurgy. The principal site, La Tolita, is thought to have been largely abandoned after 800AD, so the date of this Recuay object, from the 1st - 5th century AD does represent a period when platinum metallurgy was well-developed in these areas of Ecuador and Colombia, although there is a lack of evidence from Peru as to the extent to which platinum was utilized. For an account of Colombian sources the geological literature can be referred to (Scott and Bray 1994; Monroy 1978; Mertie 1969; McDonald 1959).

These gold-platinum alloy components represent the most Southerly extension of the use of platinum in ancient South American goldwork so far recorded. Although the Recuay cultural group is at least towards the Northern part of Peru, it is still a long way from La Tolita, and the Esmeraldas Tumaco zone in which platinum alloys are frequently encountered. Further research on the discovery of platinum in this Peruvian object is obviously necessary.

The gold alloy used to make the head and the fang, on the other hand do not contain any platinum and these are made in a gold alloy with some silver and a little copper. The copper alloy teeth were shown by X-ray fluorescence analysis to be made in a copper-gold-silver alloy with mercury being detected in the study as well. Around some of the teeth and fangs are the remains of red pigment which were shown in this. study to be made from cinnabar, the natural mineral, mercuric sulphide. Cinnabar has often been reported as a pigment from the ancient cultures of Peru and x-ray analysis was supplemented with polarized light examination which showed that the pigment had every characteristic associated with natural mineral cinnabar, ground, and used as a pigment, originally applied to the copper fangs to make them appear red. This is also an interesting discovery: the cinnabar was used to paint the copper alloy fangs to make them appear red, as if dipped in blood, and the colour contrast used in this part of the design is impressive: with the golden head, silvery teeth, golden tongue, red fangs, blue-green eyes, coppery whiskers and golden crown, the original appearance must have been even more striking than the present surfaces suggest. The surface corrosion on the crown is very unusual and suggests that some cleaning of this component mar already have taken place: further metallurgical studies are needed in order to clarify this question: one unusual finding was the discovery by x-ray fluorescence analysis that the band is made from a gold-silver-copper alloy which contains a little platinum. Platinum will lighten the colour of the gold a little and mar contribute to the unusual appearance of the slightly tarnished areas of the crown which have not been cleaned.

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Figure 18 : Recuay animal head : sample from silver colored serrated teeth. The microstructure reveals a heavily worked and annealed goldplatinum alloy matrix incorporating undissolved platinum particles, finely dispersed through the gold. The extensive and very fine scatter of the remnant undissolved platinum particles shows that a considerable attempt has been made to homogenize and disperse the platinum through the gold matrix, resulting in a very silvery colored surface to the composite material. Magnification x490, etched in aqua regia.

This Peruvian object is an unusual Huari spoon, inlaid with gold on both sides, weight 28.40 grams, dated to about 550AD - 800AD, (shown in Figure 19).

A detailed examination of this interesting and rare figurine was carried out in order to ascertain its probable cultural identity and metallurgical composition. The object is a figurine, made in silver, with a spoon at the lower end and a fanged head at the top. This head, made in silver, is hollow and has a rattle in the interior. The thickness of the silver sheet from which the figurine has been made is 0.43mm. The thickness of the flange surrounding the head is 0.83mm, confirming the visual impression that there is a double thickness of silver sheet present. The hollow, rattle head has therefore been made by joining the repoussed fanged face anta the flat backing of the spoon and body by welding or soldering the two silver components together around the perimeter of the flange.

One of the most interesting aspects of this figurine, is the very detailed inlay in gold which has been accomplished on both sides of the object. Examination of the front decorative panels reveals rather stubby hands and feet and a central design broken into a number of triangular panels. The type of design and repeated elements in these triangular panels is very suggestive of Huari designs in textile. Immediately below the line across the mid-point of the body, there are four design panels which show a symmetry also rather characteristic of Huari design. There mar be an additional face depicted immediately above the spoon, where two large round gold circles are enclosed in a holder which suggests the shape of the eye.

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Figure 19 : Huari ritual silver alloy spoon, inlaid with gold foil on both sides. Weight 28.40 grams, length 14.8 cm, 0.43 mm thick silver. The gold design is laid incised lines in the spoon and joined metallurgically with diffusion bond to silver substrate.

This same motif is repeated in an identical design, inlaid on the back of the spoon. Indeed, the entire design on the front is repeated on the back, except that the head is rendered in a series of vertical gold stripes with rows of chevrons joining them together. This chevron design is another feature which is strongly suggestive of Huari influence and is a pattern often found running around the lip of Huari pottery (Dr. Alana Cordy-Collins: personal communication: January 1996).

The face of the figurine is a fanged animal, with prominent 'N' shaped fangs which are another typical Huari feature. Sometimes these fangs occur in a backwards 'N' shape. The stylistic examination therefore strongly suggests that this unusual silver figurine is Huari from the Highlands of Peru, and dated from about 550AD- 800AD.

A non-destructive x-ray fluorescence analysis was carried out using a Kevex 0750A spectrometer, using a Ba/Sr target. The results of this study were of interest, since the silver base of the figurine was shown to contain copper, gold, lead, bromine and silver. The bromine content arises from the affinity of silver for bromine in the burial environment, leading to the formation of silver bromides and silver chlorobromides. The presence of a small amount of lead in the silver is of some interest, since lead mar be associated with the refining or extraction of silver, either by cupellation of lead ores, or by using lead as an additive in the extraction of the silver from the ores. The occurrence of significant amounts of lead, from about 0.1% - 1.5%, in ancient Peruvian silver alloys has been observed previously by Howe et al (1994) and by Scott (1996). Howe showed that some silver alloys of the Wanka culture, located in the upper Mantaro valley, were smelted from silver-lead ores which were subsequently refined by cupellation. Wanka I through III date from about 1000AD - 1500AD, with most of the silver showing evidence of lead, occurring in the later phases. The remnants of small amounts of lead are strongly indicative that similar processes mar have been used in the Huari cultural area. The data is suggestive of this possibility, but more detailed and thorough studies of a range of Huari silver pieces would have to be undertaken to really present a convincing corpus of data.

A tiny cross-section of the silver Huari spoon was mounted and prepared for metallographic examination in the usual way (Scott 1991). The polished cross-section was examined and then etched in acidified potassium dichromate solution, diluted 1:9. The grain boundaries of the silver crystals were clearly evident after etching and reveal a discontinuous precipitation which is quite typical for ancient silver, and which, in fact, proves that the object in question is ancient, for this kind of discontinuous precipitation is never seen in modern silver-copper alloys: it is an event which can only happen slowly at ambient temperatures. The microstructures are shown in Figures 20a and 20b.

The silver figurine has been gilded by the application of hammered gold foil to grooved or incised regions of the surface and the foil has been attached to the silver by diffusion bonding, which is revealed in the microstructure as a regian of dark etching below the gold surface. The use of diffusion bonding of gold foil in the Huari period has not previously been reported, partly, of course, for the reason that very few Huari objects have been examined scientifically, in fact, there is not much published information relating to the use of foil gilding in ancient South America at all. Enough work has been done to show that foil gilding was used from Peru to Costa Rica: use was made of a complete gold cladding in one sheet, and of small squares of individual gold sheet which could be partially overlapped. Macroscopic evidence for foil gilding in Ecuador has been mentioned by Bushnell (1951), Christensen (1954), Saville (1907-1910), Ubelaker (1981), and Scott (1986b), while foil-gilded pins with elaborate heads are known from Pashash, Peru, dating to the early centuries AD (Grieder 1978), although it is not certain that Grieder is correct in this matter: die pins concerned mar have been gilded by other techniques and the identification of foil gilding requires metallographic study which was not published in this case.

Foil gilding over copper was occasionally used in Colombia, sometimes for small nose-ornaments and penannular nose-rings in Panama and Costa Rica are found, often made in carved stone, with gold foil coverings (Bray 1993). Foil gilding does not appear to be restricted in a geographical or temporal sense; why this should be, when other gilding techniques were al so in use, remains unknown. From the very limited work which has been carried out it is presently impossible to link material choices within cultural areas to the use of foil gilding.