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Cracking the'genetic code' of gem stones

By: Rebecca Hancock, Category: Science, Date: 17 Jun 2009

A research team led by Dr Lin Sutherland, a Senior Fellow in Geoscience at the Australian Museum, has completed a major study on 'genetic' signatures in Australian sapphires and rubies. The study combines precise trace element and oxygen isotope analyses on samples from a range of gem deposits, for geographic typing of local characteristics.

Gem gravel

Gayle Webb © Australian Museum

Story by F. Lin Sutherland

The team analysed the levels of trace elements and oxygen isotopes in sapphires and rubies from many locations in Australia. They found that gems originating from the same location contain characteristic profiles of trace elements and oxygen isotopes and could be distinguished from gems originating from other locations.

The study, to be published in the Australian Journal of Earth Sciences, is expected to have spin-off economic benefits for the global gem trade. For example, the analysis can be used to distinguish natural stones from synthetic ones. It can also identify stones of uncertain origin.

The results are already being used in a follow-up forensic study of sapphires in a Japanese gem collection labelled only as 'from New South Wales, Australia', with no further data on the collection location. Early clues suggest the sapphires came from the Inverell (New England) gem field in New South Wales, which is renowned for its blue sapphires.

The team included mineralogists Lin Sutherland and Gayle Webb from the Australian Museum and associates and personnel from the School of Natural Sciences, University of Western Sydney; the Centre for Excellence in Ore Deposit Studies, University of Tasmania; the Centre National de la Recherche Scientifique, University of Nancy, France; the Scottish Universities Environmental Research Centre, East Kilbride, UK; and the Gemmological Association of All Japan Laboratory, Tokyo.