GIA Gem Project



About the Dr. Edward J. Gübelin Gem Collection

Dr. Edward Gübelin's study of gemstones and their inclusions extended over a professional career of more than six decades, and his work revolutionized the science of gemology. 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 The Collection

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Studying the Dr. Edward J. Gübelin Gem Collection

Since 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 color, weight, and phenomena, and they significantly enhance the educational and display potential of GIA’s gem collection.

As one of the world’s preeminent gemologists, Dr. Gübelin assembled this important collection over more than 60 years. His lifelong study of inclusions in gemstones revolutionized the science of gemology, 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 characterize 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, gemologists, researchers, and anyone interested in gem materials. Standard data collection procedures have been used, with each gemstone characterized 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 gemological properties from one locality to another within a given species. This information is lost in traditional published sources that represent compilations of gemological 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. Geographic 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 standardized 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 color according to the GIA terminology for colored 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 gemological 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, luster, long- and short-wave ultraviolet fluorescence (and phosphorescence) reactions, absorption spectra, and any optical phenomena (such as a color-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 polarizing 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 characterization. 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.

Project Contributors

Museum:
     Terri Ottaway, Curator of Collections

Laboratory:
     Mike Breeding, Research Scientist
     Karen Chadwick, Staff Gemologist
     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

Education:
     Andy Lucas, Manager, Field Gemology

Library:
     Sharon Bohannon, Visual Resources Cataloger
     Caroline Nelms, Library Research Analyst & Coordinator
     Robert Weldon, Manager, Photography & Visual Communications

Research:
     Al Gilbertson, Project Manager, Cut Research
     Brooke Goedert, Senior Research Data Specialist
     Scott Hemphill, Research Associate
     James Shigley, Distinguished Research Fellow

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