About the Dr. Edward J. Gübelin Gem CollectionDr. Edward Gübelin's study of gemstones and their inclusions extended over a professional career of more than six decades and his work revolutionised the science of gemmology. From his home laboratory in Lucerne, Switzerland, he traveled to gem localities on five continents to collect samples that he then meticulously documented. After his death in March 2005, his comprehensive collection was acquired by the GIA. The collection consists of approximately 2,800 gems representing 225 different minerals. It now forms part of the GIA Gem Collection, where it is being used for research, education and display.
Edward J. Gübelin
Studying the Dr. Edward J. Gübelin Gem CollectionSince its early years, GIA has acquired gemstone samples to support its educational and research missions. Most of these were useful for identification purposes but lacked detailed locality information and some were not particularly attractive.
This all changed in 2005 with the purchase of the collection belonging to the late Edward J. Gübelin of Lucerne, Switzerland. It consists of more than 2,800 samples representing 225 minerals and gem materials obtained from major localities worldwide. Many of the gemstones are extraordinary examples in terms of colour, weight, and phenomena and they significantly enhance the educational and display potential of GIA’s gem collection.
As one of the world’s preeminent gemmologists, Dr. Gübelin assembled this important collection over more than 60 years. His lifelong study of inclusions in gemstones revolutionised the science of gemmology and his work helped form the basis of microscopically identifying gems of all kinds. For more on Dr. Gübelin, please see the profile in the Winter 2005 issue of Gems & Gemology.
Since 2007, GIA has undertaken a project to characterise gemstones from the Edward J. Gübelin collection. This project has two main goals: to systematically document these gemstones using a range of techniques and to make the results available on the GIA website as a valuable resource for students, gemmologists, researchers and anyone interested in gem materials. Standard data collection procedures have been used, with each gemstone characterised by a range of techniques. Because the resulting data have been collected from the same individual gemstone, this database will enable interested researchers to view, for example, possible variations in gemmological properties from one locality to another within a given species. This information is lost in traditional published sources that represent compilations of gemmological information.
The project database will provide the following information on individual gemstones:
1. A photograph of the gemstone.
2. The GIA Gem Collection number.
3. A gem species name and when appropriate, a group and a variety name.
4. Geographical Locality information, reported by Country, Province or State (District or County) and Town (Mine Name), as described in the collection records obtained from Dr. Gübelin.
5. Basic information on the gemstone, such as faceted shape (reported as standardised shape names); carat weight to two decimal places (1 ct = 0.2 g); dimensions in millimeters to three decimal places; diaphaneity (transparent, translucent or opaque); and a description of the colour according to the GIA terminology for coloured gemstones.
6. Diagrams showing the shape and facet arrangement of the gemstone as seen from the top, side and bottom views. These diagrams were created from proportion measurement data obtained by the Sarin DiaVision system. They were not produced for gemstones fashioned as cabochons or other non-faceted shapes.
7. A summary of standard gemmological properties, including optic character (uniaxial positive or negative), refractive index value(s) (the maximum and minimum RI values obtained using the refractometer from the table facet of the gemstone), calculated birefringence value, a calculated specific gravity value, descriptions of any pleochroism, lustre, long- and short-wave ultraviolet fluorescence (and phosphorescence) reactions, absorption spectra and any optical phenomena (such as a colour-change or asterism). A facet-arrangement diagram is provided that illustrates the approximate location(s) of the optic axis (axes) when the direction(s) could be determined using a microscope and a glass sphere (which acts as a condensing lens) positioned above the gemstone. In this configuration and using crossed polarising filters, the gemstone is rotated until a centered optic axis interference figure is seen with the sphere. In some cases, we were unable to visually locate the optic axis of a gemstone using this method.
8. A brief general description of the internal or external features that can be seen with standard magnification (10x to ~ 100x). Many internal features were photographed through the microscope and the resulting photomicrographs are provided with captions. Photomicrographs were not taken for gemstones lacking significant internal features.
9. In most instances, several spectra are presented for a gemstone, including infrared, visible, Raman and photoluminescence spectra. An X-ray fluorescence spectrum is also provided with the major and minor elements detected.
Initial data collection has focused on corundum, spinel, garnet, beryl and tourmaline, with results obtained on approximately 1,000 gemstones. The current project is intended to provide a basic characterisation. Two important types of scientific information – a quantitative chemical analysis showing the concentrations of the major and minor elements present in a gemstone and unit-cell dimensions obtained by x-ray diffraction analysis – are not included in the project data. While there are technical challenges in gathering such information on large, faceted gemstones, we hope to add it in the future.
Information on an initial group of 50 stones (including corundum, spinel, beryl, garnet, tourmaline and other gem minerals) is presently available in PDF format. In the future, an online database will make it easier to browse and study the important gems in the Edward J. Gübelin collection. The Institute also plans to expand the database to include other stones in the GIA collection and possibly historical and important gems from other collections.
Terri Ottaway, Curator of Collections
Mike Breeding, Research Scientist
Karen Chadwick, Staff Gemmologist
Emily Dubinsky, Analytical Specialist
John Hall, Supervisor, Weights and Measures
Dylan Hand, Identification Technician
John Innis, Identification Technician
John Koivula, Analytical Microscopist
David Nelson, Metrologist
Nathan Renfro, Analytical Specialist
Andy Shen, Research Scientist
Andy Lucas, Manager, Field Gemmology
Sharon Bohannon, Visual Resources Cataloguer
Caroline Nelms, Library Research Analyst & Coordinator
Robert Weldon, Manager, Photography & Visual Communications
Al Gilbertson, Project Manager, Cut Research
Brooke Goedert, Senior Research Data Specialist
Scott Hemphill, Research Associate
James Shigley, Distinguished Research Fellow