The results of a typical XRF scan are shown in Figure 1, where the spectrum for sample C2 is reproduced. The results show that this bell, from the Department of Nariño, 8th-13th century AD, is made in a relatively pure copper containing some arsenic. The discovery of arsenical copper alloys from the Nariño area is not so surprising, since the Department of  Nariño is contiguous with the Ecuadorian border, representing the Southerly limit of the smelting of copper from arsenical ores, as we understand the data today. Nonetheless, it is interesting that arsenical copper should be found from the Nariño area and suggests the possibility that the bell is an import into the region from the Ecuadorian territory. The archaeological area of Nariño, in any case, extends into the Ecuadorian highlands. which makes the possibility for trade that much more possible. Tin bronze beads from the Nariño area nave also been reported (Scott 1980) and as more detailed analyses become available, it is very likely that further examples of either arsenical copper or tin bronze will be reported from the Nariño area.

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X-ray fluorescence analysis is extremely useful, since the objects can be examined totally non-destructively, but it is inadequate for reporting on the range of trace elements needed to characterize copper objects in order to decide whether they represent smelted copper or not. If major alloying elements such as arsenic, antimony, or tin are absent, what evidence is required of elemental composition in order to make an informed judgement? In the present study, the ICP-MS technique was employed to examine elemental composition over a range of 65 elements which, can be conveniently measured by ICP-MS to the low parts per million simultaneously. Special analytical techniques were applied additionally, to estimate low levels of arsenic, and some elements nave been quantitatively determined where they are of especial significance, such as: antimony, arsenic, cobalt, iron, nickel, silver, tin and zinc. The ICP-MS instrumentation has made very significant progress ayer the last ten years in terms of resolution, interferences, and detection limits for samples of 10mg - 30mg in weight. For the analyses, about 15mg of clean metal drillings were removed with a high speed tungsten steel twist drill.

It has become increasingly necessary to specify the full range of elements which were sought in such a detailed analysis, since, in future years, we mar Jet discover new patterns in the data and new significance to the presence or absence of a particular element: this is why the results presented here are shown for all 65 elements sought in the study: it is particularly relevant to the problem of distinguishing between native and smelted copper in ancient Colombia, since very few objects made in ancient Colombia do not contain gold and silver, even if present only in the parts per million, since contamination with gold on melting and casting would be highly probable; gold being a universal commodity in Colombia as far as the metalsmiths are concerned. The occurrence of elevated trace amounts of gold and silver in the copper alloys hinders any possible inferences concerning copper sources based on these two elements. It is also common for native gold in Colombia to be contaminated with small amounts of copper from melting without the alloy necessarily being a deliberate tumbaga alloy, although this kind of alloy is also difficult to characterize since native gold, besides silver may also contain copper, although this is usually less than 1 %.