IVORY CHARACTERIZATION USING PORTABLE VIBRATIONAL SPECTROMETRY

Abstract

Ivory was commonly used in the manufacture of numerous objects. It refers to the tusk and teeth of animals. Almost all ivory pieces, in the past, found on the market were authentic; however, nowadays, ivory extraction is an illegal practice. Thus, official government and animal protection entities have been fighting intensely against this criminal practice, but the production and sale continue. There are numerous difficulties in identifying the illegal extraction and use of ivory, and the correct characterization is certainly a significant challenge. A proper ivory characterization is an important tool in the fight against ivory extraction once it is possible to trace the piece to the animal and sometimes even to its origin. It is also useful for museums and art collectors to verify the authenticity of the piece. Ivory, also known as the inorganic gemstone, is composed of calcium phosphate, collagen, elastin, and lipids. Different tests can differentiate ivory from bones or celluloid; however, some can damage the piece. Because of that, analytical techniques are preferred. However, the method to be used must have the capability of differencing small differences once the chemical elements present in ivory, bone, or even celluloid are the same. In this work, three analytical methodologies were used to check the possibility of having an alternative test applied on supposed ivory samples. All three methods used, X-Ray Fluorescence (XRF) and vibrational spectrometry techniques (FT-IR and Raman), are portable equipment to facilitate the analysis in situ. FT-IR and Raman spectra obtained had shown differences between bone and ivory samples, indicating the art collector samples are probably ivory. These differences allied with the portability of the analysis can be used as an additional test to be done in ivory and bone-based materials.