About Us

Bear Bear Williams, CG, FGA, President, Laboratory Director
Bear travels to gem producing countries and treating regions researching the latest trends in gemology and visiting with other lab directors. On-site research allows him to keep abreast of new synthetics and treatments in the marketplace. Bear is   Co-Chair for the Gemological Industry and Laboratory Conference. The GILC conferences bring top gemological leaders together to present research findings and discuss the latest nomenclature or laboratory issues relevant to the trade and consumers. Increasingly recognized as an expert in the field of digital spectroscopy, Bear operates UV-Vis-NIR, ED-XRF, FTIR, and Raman spectrometers.
cara Cara Williams, FGA, Staff Gemologist
Cara, vice-president and senior staff gemologist for SGL, is a fellow of the Gemmological Association of Great Britain (Gem-A). Cara is also an active tutor for the prestigious Diploma in Gemmology course for the Gem-A in London. She brings a lifetime of experience working with gems to both the lab and her students. Growing up in the retail end of the business, with a concentration in colored stones, Cara has been in the wholesale trade since 1986.  Bear and Cara together serve as advisors to The Guide, a respected trade reference manual, and have written their reference guide on opals.
donald Donald Hoover, PhD, FGA, FGAA (Hons.) Research 
Don Hoover brings a wealth of international scientific experience to Stone Group Labs from his years as a geophysicist with the U.S. Geological Survey. Don has published extensively on both mineralogical and gemological topics, including the book, Topaz, the definitive book on the topic.  His innovations in new gemstone testing methods have been the topic at several gemological conferences.  Dr. Hoover is currently researching the various garnets species.

Stone Group Labs is also happy to have on our Board of Advisors:

  • Robert T. Downs, Ph.D. Professor, Department of Geosciences, University of Arizona
  • Mary Johnson, Ph.D. in Mineralogy & Crystallography, Harvard University, President: maryjohnsonconsulting.com
  • Grant Pearson, FGAA, Researcher, Author, Melbourne, Australia
  • D. Brian Thompson, Ph.D., Professor, Department of Physics and Earth Science, University of North Alabama




Copyright 2016 Stone Group Labs LLC