A Case Study of Ivory Species Identification Using a Combination of Morphological, Gemmological and Genetic Methods

Twenty-one items sold as mammoth ivory in China were submitted to the Zurich Institute of Forensic Medicine (University of Zurich, Switzerland) and SSEF for testing. The aim of this case study was to identify these samples using macroscopic morphological diagnostics, microscopic examination, FTIR spectroscopy, trace-element analysis and additional minimally destructive DNA analysis (of approximately 100 mg of powder) of a region of the cytochrome b gene to assign taxonomic identification. Morphological features (Schreger angles) shown by five of the samples were characteristic of extinct Proboscideans (mammoths), and one other specimen displayed unnatural layering that identified it as an ivory imitation. FTIR spectroscopy further showed the imitation was an artificial resin, while infrared spectra of the other samples displayed overlapping features characteristic of carbonated hydroxyapatite (i.e. ivory or bone). Like FTIR spectroscopy, trace-element chemistry cannot be used to separate species. DNA analysis could in some cases differentiate extinct (mammoth) from extant (African and Asian elephant) Proboscidean species, and also identified one specimen as cattle bone. Combining morphological, gemmological and genetic approaches can increase the amount of evidence available to identify the species origin of ivory. (C) 2020 Gem-A (The Gemmological Association of Great Britain)