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Chromium and Corundum


#1

In regards to the discussion of rubies versus “red sapphires”; I was
moved to call my instructor at GIA who consulted with a total of four
individuals at the Lab before answering my question. The unanimous
pronouncement of that group was that red corundum without chromium
does not exist. They say corundum can only achieve red color through
chromium. According to them GIA confers identity in rubies by color;
so that if at some point a non-chromium, red stone were discovered it
would still be classified as ruby by GIA. They speculated that there
might be some confusion in this issue because there is a difference in
the GIA and European standards for emeralds, which are classified by
color here and according to chemistry in Europe, where the standard
requires chromium, while GIA standards include vanadium colored beryl.
Sounds like we need to confront GIA with the disparate opinions
their experts are handing out. At least for the time being I will
feel quite comfortable offering red Umba stones on my site as ruby.

Barbara
Barbara W. Smigel, PhD.
Colored Stone Graduate, GIA
Artistic Colored Stones
840 S. Rancho Dr. #4387
Las Vegas, Nevada 89106
(702) 382-0694
website: http://www.acstones.com
email: @smigel