Materials, archaeological composition

Most of the methods and instiiimcnts discussed in this book are concerned with the analysis of the composition of organic and inorganic materials. These procedures aie designed to identify the elemental, isotopic, or molecular structure of the material. Archaeological chemistry at the organic level is particularly complex and the next section provides some terms and concepts of importance in understanding this subject. 

Most of the essential information on archaeological materials is derived, at the present time, using physical methods of analysis. This may include the qualitative or quantitative assessment of their composition, their provenance, the techniques used for their production, and their age. Some of the most widely used methods of chemical analysis based on physical principles are succinctly reviewed in the following paragraphs. 

Common ancient ceramic materials often found in archaeological excavations, such as fired brick and pottery, were made mostly from a mixture of a secondary clay and fillers. The nature, composition, and properties of clay have been already discussed the nature of the fillers, the changes undergone by the clay as well as by the fillers during their conversion to ceramics, and the unique properties of ceramic materials, are reviewed in the following pages. Attention is drawn also to studies that provide information on the composition and characteristics of ancient ceramic materials. 

Many material properties lend themselves to the authentication of objects the composition and the physical and chemical properties of materials and their decay products provide objective criteria for establishing the authenticity of archaeological objects. Contradictions between the claimed origin or... 

Freestone, I. C. (2005), The provenance of ancient glass through compositional analysis, in Vandiver, P. B., J. L. Mass, and A. Murray (eds.), Materials Issues in Art and Archaeology VII (Symposium, November 30-December 3, 2004, Boston, Massachusetts), Materials Research Society Symposium Proceedings, Vol. 852, Materials Research Society, Warrendale, Pennsylvania. 

The results show that DE-MS alone provides evidence of the presence of the most abundant components in samples. On account of the relatively greater difficulty in the interpretation of DE-MS mass spectra, the use of multivariate analysis by principal component analysis (PCA) of DE-MS mass spectral data was used to rapidly differentiate triterpene resinous materials and to compare reference samples with archaeological ones. This method classifies the spectra and indicates the level of similarity of the samples. The output is a two- or three-dimensional scatter plot in which the geometric distances among the various points, representing the samples, reflect the differences in the distribution of ion peaks in the mass spectra, which in turn point to differences in chemical composition of... 

This section details the mass specta of reference molecular constituents and of various substances including waxes and vegetable oils that were recently investigated in order to establish comprehensive correlation between the mass spectra obtained on archaeological and museum samples and the main organic materials involved in their composition. 

Although beeswax is a very stable and chemically inert material, studies have verified that the composition of beeswax found in archaeological environments may show some significant alterations compared with that of fresh material. The main changes observed are due to ... 

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