Research project titled “Characterization of species from bone, tusk, rhino horn and antler to deal wildlife offence cases” commenced in July 2001 is aimed to characterize ivory, antler, bones and rhino horn using various techniques. In the present study, attempt was made to characterize ivory of Asian and African elephants using Schreger Angle Measurements, Thermo Gravimetric Analysis (TGA), Elemental Analysis [X-ray Fluorescence (XRF), Atomic Absorption Spectroscopy (AAS), Inductively Coupled Plasma - Atomic Emission Spectroscopy (ICP-AES), and Inductively Coupled Plasma - Mass Spectroscopy (ICP-MS)] and Stable Isotopic Analysis.  

Schreger angle is characteristic of dentine part of elephant ivory, and was recorded at three different zones in ivory samples of African (n=12) and Asian  (n=23) elephants. The relationship between Schreger angle and circumference of Asian elephant ivory was also examined. 

Approximately 10 mg of sample was used for TGA analysis and percentage weight loss at different segments of temperature (25oC – 1400oC) was observed for Asian (n=6) and African (n=6) ivory. The nature of weight loss was different in some temperature zones between Asian and African ivory and serves as a species-specific signature. Overall percentage of weight loss of Asian ivory and African ivory was 47.15% and 48.15% respectively. Elemental (n= 40) analysis of ivory was carried out in Asian and African ivory by XRF, AAS, ICP-AES and ICP-MS to provide preliminary data.

Stable isotopes viz. carbon, nitrogen and strontium have been widely used to ascertain source of origin of elephant ivory. Presently, we determined isotopic ratio of carbon (n=31) and nitrogen (n=31) corresponding to diet and rainfall respectively. Reference ivory samples from five areas within India were analyzed using collagen and powder sample and later one was found more suitable for forensic analysis. Approximately 1 mg of sample was used for each isotope. Maximum and minimum ä13C value of the analyzed samples was –13.6±0.15 ‰ and –25.6±0.15 ‰ respectively. Maximum and minimum ä15N value of the analyzed samples was 10.2±0.15‰ and 3.5±0.15‰ respectively. Relationship between isotopic ratio of carbon and nitrogen clearly separates tusks in two zones except a few samples. Work on this aspect is in progress.