CO2 diamond slice, SGDF-5864, under UV excitation (220 nm). Micrograph Dr. T. Hainschwang

conference on Replay: Brown Diamonds, a new in-depth look at their properties and classification

  For those of you who missed out on Thomas Hainschwang's speech which covered Brown Diamonds, during the 4th AIGS Gem Tips program. Here is your chance to view it again.



Brown Diamonds, a new in-depth look at their properties and classification

Brown diamonds are – together with yellow diamonds – among the most common diamonds in the market. They are currently more affordable than most other fancy colour diamonds, with exception of cloudy grey and black diamonds, but the market asks more and more for brown diamonds, which might give the value and appreciation of such diamonds a boost in the years to come. This study is a continuation of the work of the author, who has done research on the topic of the classification of brown diamonds for his DUG diploma from 2002 to 2003.

Brown diamonds can be categorised in two very broad categories, into those owing their colour to defects related to plastic deformation, and those that do not owe their colour to plastic deformation. The extensive work done on brown diamonds since then and particularly for this study has allowed us to get a much deeper insight into this large and complex group of diamonds, and to elaborate a more detailed modified classification of brown diamonds than the one published between 2003 and 2004.


About the speaker

Dr. Thomas Hainschwang is Director and co-founder of GGTL Laboratories (GGTL Laboratories Liechtenstein, formerly Gemlab Liechtenstein, founded in 1996). Dr. Hainschwang has been working on the analysis of diamonds, coloured stones and pearls for the past 23 years, and is a respected expert in the field of gemmological research, with extensive experience in the complex topic of coloured diamond. Besides his expertise as a multidisciplinary gemmologist with specialization in diamond research and testing, Dr. Hainschwang has developed and built many analytical instruments for gem and pearl testing in the past years. He has published over 150 articles on various gem related topics and has presented these topics in more than 100 conferences around the world. He received the prestigious Antonio C. Bonanno Award for Excellence in Gemology in 2015 and the Gemmological Excellence Award of the Swiss Gemmological Society in 2017, both Awards that recognize those who have made significant contributions to the gemological field.

Dr. Hainschwang holds a PhD in Physics (materials science) from the University of Nantes, France, that he obtained in May 2014 with his dissertation, Type Ib diamonds: Correlations between the physical and gemmological properties of diamonds containing isolated nitrogen.