About Us

Bear Bear Williams, CG, FGA (Hon), 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. He regularly meets with other gemological associations and labs, and together will present research findings, and discuss the latest nomenclature or laboratory issues relevant to the trade and consumers. Recognized as an expert in the field of digital spectroscopy, Bear operates UV-Vis-NIR, ED-XRF, FTIR, UV, 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 has been a tutor for the prestigious Diploma in Gemmology course for the Gem-A in London for more than 15 years. Growing up in a retail jewelry family with a concentration in colored stones, Cara has been in the wholesale trade since 1986. She brings a lifetime of experience working with gems to the lab, her students, and many published articles.
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 has contributed new methods of research into the various garnets species. His current research has focused on the long-elusive source of alluvial diamonds of the Alto Parnaiba in Brazil.

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 2019 Stone Group Labs LLC