Gemstone Spectra
Contributed
by Grant Perarson
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 |
Other Synthetics |
| Alexandrite |
|
Amblygonite |
|
| Beryl,
non-emerald |
|
Apatite |
CZ (cubic zirconia) |
| Emerald, natural |
Emerald, synthetic |
Axinite |
|
|
|
Corundum, synthetic |
Benitoite |
GGG (gadolinium gallium garnet) |
| Garnet |
|
Brazilianite |
YAG (yttrium aluminum garnet) |
| |
|
Diaspore |
|
| Spinel, Natural |
Spinel, Synthetic |
Ekanite |
|
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, http://minerals.gps.caltech.edu, 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
<gpearson@netspace.net.au>