Gemstone Spectra

Contributed by Grant Pearson

Mt. Waverley, Victoria, Australia

This Spectra Compendium is a collection of numerous specific examples of gem spectra of unusual materials and material varieties from particular locations. The spectra have been determined on a dual-beam, computer-interfaced UV-Vis Cary-3 spectrophotometer capable of recording signals to an absorbance of 10. They are taken without a polarizer. Many samples are oriented in 2 or more directions to show the dichroism or pleochroism of the materials. The spectra are not necessarily oriented along crystallographic directions.

Common Stones Synthetics Less Common Stones Less Common Stones
Alexandrite   Amblygonite
Corundum, syntheticAmphibolesHamburgite
Beryl, non-emerald
Apatite Jeremejevite
 CZ  (cubic zirconia)AragoniteKornerupine
Emerald, natural  Emerald, synthetic Axinite Kyanite
Corundum, natural
GGG (gadolinium gallium garnet) Benitoite Paraisite
Garnet  Spinel, synthetic Brazilianite Phenakite
 YAG (yttrium aluminum garnetCarletonitePyroxenes
  Cordierite (Iolite)Rhodonite
      Datolite Sinhalite
Spinel, natural  
Diaspore Sillimanite
  EuclaseTitanite (Sphene)
    Zoisite (Tanzanite)

More of this collection will be come in the future  ....

About The Contributor:

Grant Pearson, the compiler of these uv-vis spectra and accompanying descriptions is a metallurgist by training, having spent his undergraduate years and first decade of working life at the University of Melbourne.  He graciously provided these spectra for display on this site,, for the benefit of  a broader audience. He developed gem-faceting skills for relaxation, and has then taught faceting classes at one of the larger Gem Clubs (Waverley) in Melbourne prior to undertaking the Gemmological Diploma course of the Gemmological Association.  For about the last decade or so, he has delivered lectures on gemological instruments and their use, opal, rare stones (of which a comparatively extensive reference collection has been assembled that formed the basis of the selection of materials that have been here investigated spectrophotometrically), as well as various “Popular Gemmology” lectures and “Emerald Update” workshops for the Victorian Branch of the Gemmological Association.  Many of the annual Gem-Club Exhibitions in Melbourne are regularly attended on the behalf of the Association to provide a gem identification and authentication service, and to promote the Gemmological Association and its educational and lapidary courses.  A process was also developed for manufacturing the organic components of the high-refractive-index contact liquid for use with gem refractometers, which is still being utilized by gemologists and students and in several State Branches of the Australian Gemmological Association.

PLEASE NOTE:  All original material presented on this website is copyrighted to the author, Grant Pearson.  Requests or enquiries to the writer for their reproduction can be directed by email through <>