The AIGS is the Asian Institute for Gemmological Sciences.
It is one of the finest gem labs in the
That being said, I can't think of any reason to buy online.
Why don't you work with local jewelry stores in your community? See
the gems in person! Have a gemologist explain color change, cutting
quality, and the difference in character of alexandrite from
different localities to you IN PERSON with examples.
In the United States, for colored gems, I personally prefer a
certificate from the American Gem Trade Association.
An excellent site with a lovely explanation of
alexandrite is Pala in San Diego:
Hope this helps.
Barbra Voltaire, F.G.G., G.G., N.A.J.A.