ORIGIN AND SPECIES DETERMINATION OF ORGANIC GEMS: DNA FINGERPRINTING AS A NOVEL METHOD IN GEMOLOGY

Organic gems such as pearls are some of the oldest gems collected and used in jewelry by mankind. Although not geological in origin, organic gem materials such as corals, ivory and pearls are products of biomineralization processes.

Organic gems such as pearls usually contain minute amounts of organic matter bound by a mineral matrix. This organic matter may contain small amounts of DNA that can be extracted and analyzed using novel extraction and fingerprinting techniques. This method was developed and published in 2013 using different types of pearls and oyster species (Meyer et al., 2013). This method has been further refined so that the pearl does not need to be destroyed (i.e. quasi non-destructive) and the amount of required material has been considerably reduced.

This innovation offers a number of testing and marketing opportunities within the billion US$ international pearl industry. DNA fingerprinting can offer conclusive identification of the oyster species to which a pearl corresponds. Furthermore, the method has the potential to reveal the geographic origin of a pearl –which is an important factor for the valuation of pearls- based on more specific fingerprinting.

Although this method has only been applied to pearls thus far, it is currently being tested for precious coral and ivory. Past destructive research on ivory samples showed that it is possible to determine the regional origin of an ivory sample based on extracted DNA (Wasser et al., 2004). Furthermore, this method can be applied to other gem-relevant materials such as giant clam shells and (precious) corals. The novelty of this method is its quasi non-destructive nature, which makes it highly interesting for the jewelry industry. This research is also very relevant to the work of international customs within the context of organic gems protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

This method can increase transparency (through origin and species determination) and prevent fraud by identifying protected species for other organic gems. DNA fingerprinting as a tool in gemology illustrates the importance of collaborating with researchers from other fields in order to develop new gemstone testing techniques for the 21st century.