In an effort to ensure political stability and eliminate human rights abuses in certain African countries, the outgoing U.S. Presidential administration convened the "White House Diamond Conference: Technologies for Identification and Certification" in Washington, D.C., on January 10. This one-day conference addressed the need to eliminate conflict diamonds (e.g., those mined from rebel-controlled areas in Angola, the Democratic Republic of the Congo, and Sierra Leone) from international commerce. The objective was to determine if technology is in place—or could be developed and perfected within the next five to 10 years—to identify or track rough and polished diamonds from specific regions of origin through the jewelry trade to the consumer. This goal should be accomplished without disrupting or penalizing the legitimate diamond trade, including the economies of African countries that depend on legitimate diamond exports, such as Botswana, Namibia, and South Africa. According to current estimates, conflict diamonds account for less than 4% of the world’s rough diamond production.

The conference brought together 132 participants from governments, the diamond industry, companies with specialized technologies, academia (including museums), and humanitarian nongovernmental organizations (e.g., Global Witness, Amnesty International). Most of the participants were policy makers, scientists, and engineers from the U.S. Also present were technical personnel from Canada, Great Britain, Belgium, and Israel, as well as diplomatic representatives of countries involved in the diamond trade.

A plenary "background" session explained the complexities of the diamond industry to conference participants who were not involved in the trade. Recurrent themes were:

• The long-term harm that negative publicity associated with conflict diamonds could cause the jewelry industry

• The recognition that, with the knowledge presently available, it is not possible to certify the country of origin of individual diamonds, either rough or polished

• The difficulty of completely eliminating trade in conflict diamonds in impoverished societies where corruption exists.

The World Diamond Council (represented by Eli Izhakoff) strongly supports a global rough-diamond certification program, such as the proposed "System for International Rough Diamond Export and Import Controls," as the only feasible approach to the conflict diamond problem at this time (to view a copy of the document, visit www.worlddiamondcouncil.com). Yet the intricacies of the diamond "pipeline" (described by Jeffrey Fischer of the Diamond Manufacturers and Importers Association of America), in which diamonds mined in 22 countries often go through numerous mixings and trans-border crossings before they reach the cutting factory, makes any control system a challenge. The Belgian High Diamond Council (HRD, represented by Mark van Bockstael) recently helped implement a prototype certification program for legitimate diamonds from Angola and Sierra Leone.

The following session, on measuring chemical and physical properties of diamonds to determine their country of origin, focused on diamond formation in the Earth’s interior and subsequent transport to the surface (Prof. Stephen Haggerty, University of Massachusetts), chemical and isotopic analyses (Prof. Roberta Rudnick, University of Maryland), and spectroscopic characteristics (Prof. Lawrence Taylor, University of Tennessee). Notwithstanding the possibilities suggested by many advanced and sophisticated techniques and instruments (e.g., determinations of trace elements and C, N, O, and S isotopes in diamonds and their inclusions by various forms of mass spectrometry), no chemical or physical method is sufficiently definitive to be practical for determining the country of origin of a diamond.

Dr. Jeff Harris (University of Glasgow) noted that experts can sometimes classify the geographic origin of some rough diamonds with a high degree of confidence on the basis of external morphology (see, e.g., figure)—particularly with "run of mine" parcels. However, mixing of rough diamonds from different sources can defeat the authenticity of such determinations. The likelihood of recognizing rough diamonds from Angola and Sierra Leone is also severely hampered by the fact that the vast majority of the conflict diamonds in these countries are alluvial in origin, so they probably originate from several primary sources (possibly in neighboring "nonconflict" countries).

The task of determining a diamond’s country of origin becomes quite daunting when the actual magnitude of the diamond trade is realized. One of us (JES) informed the conference participants that over 800 million polished diamonds enter the market annually, and the vast majority are small stones weighing about 2–3 points on average (mostly cut in India). Furthermore, all the potentially useful methods to analyze the chemical or physical properties of diamonds or their inclusions require expensive equipment, highly trained personnel, and lengthy timeframes. A large database of information about the chemical and physical properties of diamonds from each producing country (and mine) would be required to make such techniques definitive, and no such database (or collection of diamonds from which it could be developed) yet exists.

Since there is currently no method to chemically or physically "fingerprint" diamonds for provenance, the final morning session on technologies to support a global certification program became more relevant. Simon Pitman represented the De La Rue company, which has been in the business of supplying secure and authenticated products (e.g., securities and bank notes) for over 200 years.

In cooperation with the Belgian HRD, this company is now engaged in developing the secure certification necessary for the movement of legitimate diamonds from Angola and Sierra Leone. The De La Rue methods appear to employ technologies similar to those used by the U.S. Secret Service (represented by Dr. Antonio Cantu) to combat counterfeiting or alteration of legitimate currency and documents.

Several novel suggestions were presented for "tagging" (i.e., uniquely identifying) individual diamonds. Instrumentation manufactured by Gemprint Corp. (represented by Hermann Wallner) records the reflections of laser light on or through a fashioned diamond. According to Mr. Wallner, the reflection pattern for each diamond is unique (because of slight differences in the angles between polished faces) and can be stored in a database to help track a diamond after polishing. At present, however, this technique is not applicable to rough diamonds, and the Gemprint "signature" may be altered if the diamond is repolished. Sarin Technologies (represented by Zeev Leshem) offered the possibility that individual rough stones could be uniquely identified and subsequently tracked by "mapping" their surfaces with proprietary proportion measurement machines. Also of interest was the concept (called Gemtrac) proposed by 3Beams Technologies (represented by Dr. Jayant Neogi) to brand and track diamonds from the mine to the consumer. In this scenario, individual diamonds would be given a "bar code" at the mine—either directly on the rough diamond, or encapsulated in a biodegradable polymer that would also hold the diamond. This means of identification would accompany the diamond through the polishing stage and eventually to the consumer. All transactions involving the diamond would be stored in a central database.

For the second half of the conference, participants were divided into four groups based on their expertise, and then reassembled for final discussions. The "Chain of Custody" group discussed methods to expand certification programs globally in a practical and cost-effective manner, without penalizing legitimate producers or burdening the entire industry with increased costs. The "Tagging Technologies" group observed that the proposed suggestions for tagging individual diamonds (see above) were probably not yet practical. However, the group considered the laser tagging of individual large and valuable stones as a possible alternative.

The "Spectroscopic Analysis" group recognized that reference diamonds from specific mines and countries are not available for study, and that without such diamonds it is not possible to determine if there are locality-specific diagnostic spectroscopic features. One member of the group (Prof. George Rossman, California Institute of Technology) presented an imaginative method for determining the latitude from which a diamond originated and, by inference, the country in which it was mined. This technique uses the hydrogen and oxygen isotopic composition of clays found on the surface (e.g., within minute crevices) of rough diamonds. However, a thorough cleaning of a diamond (to remove the clay) or treating the specimen with clay from a different locality could defeat this approach.

The "Chemical Analysis" group also noted the need for reference diamonds from specific mines and countries. There is potential for characterizing parcels using physical features (e.g., morphology, color, inclusions), perhaps assisted by studies of chemical characteristics of individual diamonds, but much more work is needed. Also, identifying chemical variations in diamonds will require very sensitive and expensive techniques such as ion microprobe analysis and laser ablation mass spectrometry; these are also somewhat destructive. Although the use of bio-tracers, pollen, and other materials that might be retained on the surface of a rough diamond was mentioned, they are likely to have limited utility. It will be difficult to prove that the data provided by any of the chemical methods from a single diamond is absolutely unique to a deposit or country of origin.

In conclusion, no definitive scientific means exists today to identify the country of origin of a diamond. Although "tagging" systems are available that could help document the movement of diamonds from mine to market, none of the methods suggested thus far is practical for dealing with the millions of carats of rough diamonds mined each year. It appears that the only hope to deal with conflict diamonds in the near future rests with a multinational certification system (such as the World Diamond Council proposal mentioned above) that authenticates the movement of legitimate diamonds.

Alfred A. Levinson
University of Calgary, Alberta, Canada

James E. Shigley
GIA Research, Carlsbad