Artifacts copper

The blue-green coating or patina on many bronze statues and copper artifacts often adds to the authenticity of the art. Less desirable... 

Gersch, H. K., Robertson, J. D., Henderson, A. G., Pollack, D., and Munson, C. A. (1998). PIXE analysis of prehistoric and protohistoric Caborn-Welbom phase copper artifacts from the lower Ohio River Valley. Journal of Radioanalytical and Nuclear Chemistry 234 85-90. 

John Brereton describes the copper artifacts of the Indians of Virginia. 

The composition of bronze artifact corrosion products excavated from several lacustrine sites could be explained in relation to some characteristics of the environment. In one study, a combination of potential pH diagrams for copper and those defining different types of natural soil was used to explain the composition of corrosion products of copper artifacts excavated from different locations. While sulphides are predominant in anaerobic conditions, mostly carbonates are... 

Clearly the procedures of the laboratories involved in this project could be improved. Before suggesting methods of improvement, one obvious point should be stressed. The results of this study do not vitiate the use of data between laboratories they merely indicate that the data should be used with caution. For example, in the Luristan bronzes (14), the arsenic content of arsenical copper artifacts is said to drop from 2-6% to 2% and below after a tin-copper alloy was introduced about 2600 B.C. If another laboratory analyzes a copper alloy object and finds, say 4.9% arsenic (and all other factors agree), the object can be confidently set into the earlier group if the laboratory finds 0.8% arsenic, the object could be set into the later group. If the arsenic content is 1.95%, the grouping into which it would fall is less unequivocal, and other factors... 

Unfortunately, coppers prime attributes, malleability and ductility, are also its biggest negatives. Copper is too soft to take and hold an edge. Thus, the earliest uses of lead and copper were likely decorative. Archeologists have found thin hammered copper plates attached to cloth, and lead beads strung on a necklace. The earliest cast copper artifact found so far is a mace head made around 5000 b.c. in Asia Minor. 

The application of lead isotope analyses to provenancing almost pure copper artifacts seems relatively straightforward in most instances, but what of arsenical copper and tin bronze alloys In principle, the arsenic in arsenical copper may have been derived from high-arsenic minerals (such as tennantite or basic copper arsenates) containing lead of a different isotopic composition from that of the copper ore used to produce the copper. However, absolutely no archaeological or other evidence of proves that this was ever done in the Bronze Age Aegean. On the contrary, at Kythnos definite evidence shows that arsenical copper was produced in EBII times from arsenical copper ores of variable (sometimes zero) arsenic content but of uniform lead isotope composition. 

Some of the objects from Kastri falling in Trojan field B need further discussion. Four of these objects (16167, 16169, 16171, and 16174) have lead isotope compositions that resemble the fingerprint of Cypriot copper ores however, we have rejected the hypothesis that these metal objects at Kastri are Cypriot in origin by comparing their trace elemental composition, particularly gold and silver content, with some Cypriot copper artifacts excavated on Cyprus. The results of the neutron activation analyses of these objects are presented in Figure 11. 

In addition to the analysis of physical structural characteristics of textile fabric pseudomorphs, chemical information has been obtained. On bronze and copper artifacts, the pseudomorphs are composed of malachite, tenorite, and cuprite (I, 2), the formation of which probably requires moist conditions, a corrosive metal, and optimum fiber-metal contact (I). Trace elements in their structure vary from object to object and site to site (1-3), but the relationship of these elements and the fiber, metal, and soil composition is not yet known. 

Prehistoric Copper Artifacts in the Eastern United States... 

The results of this cluster analysis is shown in Figure 1. Three broad clusters are evident from this figure Cluster I, the southwestern ores and those from Virginia Cluster II, the southeastern ore sources and Cluster III, ore sources from Michigan and Wisconsin and the Copena copper artifacts. 

Table IV. Copper Artifacts Used in This Analysis...

Figure 3, Distribution of copper artifacts at regional and local transaction...

The Discriminant Function d. In order to assign a copper artifact to the copper deposit of most probable origin, it is necessary to use statistical techniques compatible with the data. Several discriminant func-... 

Table I. Concentration of 27 Elements from Analyses of Native Copper and Native Copper Artifacts...

To illustrate the range of trace element abundances throughout the intervals through I5 for all native copper in the data base, Table I combines the 586 analyses of native copper samples from deposits throughout the world with the 441 analyses of native copper artifacts from North America. 

Table VI. d Assignments of Copper Artifacts, Houska Point Site, Minn.

In Europe and the Middle East, the appearance of copper artifacts in the archaeological record is significant enough that the term Chalcolithic - or Copper Age -was added to the tripartite stone-bronze-iron age system. Other regions such as the upper peninsula of Michigan, which has an abundance of native copper, also recognize ancient Copper cultures (Fig. 3.7). Copper must have been an attractive and useful material to prehistoric peoples. The earliest examples of copper are in the form of pendants and jewelry. 

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