March 2010
Recent additions or
amendments
Principal Gemstones;
Two new pages have been added to the
site. These are DIAMOND (Cape Series
)and CHRYSOBERYL (Yellow Brown and Green)
To view these pages go to the
SPECTRA DATABASE and follow the links in the column on the left.
Next one in preparation is
Blue and Green Spinel
A note to students of
the International School of Gemmology San Antonio USA
Thank you for your
encouraging remarks on this web site. I hope you find the content of some
assistance with your studies.
January 2010
Recent additions or
amendments
Website
This is the new look to my
web site and I hope you find it viewer friendly and simple to navigate.
Spectra
Database
Principal Gemstones;
Three new pages have been added to the
site. These are GREEN JADEITE,
SYN. BLUE SPINEL & COBALT GLASS and SYN. COLOUR CHANGE CORUNDUM.
To view these pages go to the
SPECTRA DATABASE and follow the links in the column on the left.
Colour Filters;
This is a new section which is undergoing
construction consisting of various colour filters used in gem testing.
Details and images of these filters and their spectra will be included with
spectra of gemstones associated with their use. Hopefully this will be
uploaded in the near future if I can find a 25 hour day.
Orange Gemstones;
This is the next section to be added to the
Gemstone Comparison Spectra. Several images are ready to build another Excel
file but again that rare commodity - TIME - seems to elude me. So watch out
for gems such as Spessartine Garnet and the rare gems Bastnaesite and
Parisite.
And finally my best wishes
go to all my viewers for a prosperous and healthy New Year in 2010
November
2009
Recent additions or
amendments
Spectra Database
Now that
Gem - A have decided to present gemstone spectra to read 400nm. on the left
in their gemmology course notes I have amended my images accordingly. My
poor confused brain is gradually adjusting after more than half a century
using my spectroscope in the reverse direction. The pages of my spectra
database compiled so far now show both versions of spectra 400-700nm. and
700-400nm. This will continue for a limited period and will gradually be
phased out, as it increases the work load considerably. I have also recently
converted my spectra of the commercially important principal gemstones
to read 400- 700nm. which is what our future students will come to expect.
Gemstone
Comparison Spectra
Colourless gemstones;
A better image of the garnet top doublet in
CS1. now shows the thin slice of garnet on the table facet.
Red gemstones;
Chondrodite and Epidote have bee added to
RD1.and Tourmaline has been added to RD4.
Pink gemstones;
Three pink groups have been added to the
database.
Principal Gemstone Spectra
Alexandrite;
I have at last managed to capture the
fluorescing emission doublet in the red on camera. This synthetic stone is
remarkably similar in colour both in daylight and tungsten light to
synthetic colour change corundum so beware not to rely on appearance alone.
Gem - A
Conference London October 2009
Life's full of surprises -
nobody tells me anything! I felt very honoured to be presented with the "R.
Keith Mitchell Award for Gemmological Spectroscopy" and I thank all those
who thought me worthy of this achievement. It was good to meet friends and
colleagues again and I hope those who attended my workshop found some
inspiration to further their expertise in the use of the spectroscope.
Thanks to all for your courtesy to Kathleen and myself in the magnificent
setting of Goldsmiths Hall
John and Kathleen Harris.
Copyright John S.
Harris 2000-2010 |
Gemlab.UK
Gemmological Research and Education