Pottery, archaeological materials chemical analyses

Sampling. Concentrations of carbon in archaeological materials range from very large in charcoal to less than 1% in metals, foundry slags, and pottery. The size of the sample needed for analysis, thus, depends on the nature of the material as well as its age. The analytical procedure used to isolate the carbon may result in significant losses during extraction and chemical conversion. Samples should always be taken in sufficient quantity for replicate determinations and comparison with control specimens. 

Using a portable beam stability-controlled XRF spectrometer, Romano et al. (2005) have determined the concentrations of Rb, Sr, Y, Zr, and Nb in 50 fine potsherds from the votive deposit of San Francesco in Catania (Italy) by using a multilinear regression method in their bid for quantitative nondestructive determination of trace elements in archaeological pottery. A small portion of a few potsherds was even powdered in order to test the homogeneity of the material composing the fine pottery samples and the XRF data were compared with those obtained by chemical analysis of the powdered samples. 

Neutron activation analysis (NAA) is an eminently suitable technique for obtaining the chemical profile of ancient pottery and artifacts made from other earthy materials. This technique can be used to determine where these articles originated. An NAA system that has proved to be adequate for this task is discussed. A brief review is also given of the way archaeologists have decided matters of provenance and the uses to which they put their knowledge. Finally, two examples of archaeological problems are given in which the new horizons opened by the laboratory work are stressed. 

The thermal analysis of different archaeological samples of bricks, terra-cotta, and local clays provides useful information on the chemical composition of historical samples and can provide confirmation of specific sites of originJ ] The thermal characterization of local clays is valuable to assist the restoration of historical pottery materials. 

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