Micro-World Gems & Gemology, Winter 2017, Vol. 53, No. 4

Vesuvianite in Burmese Ruby

Yellowish green vesuvianite crystal in faceted Burmese ruby.
This vibrant yellowish green crystal in a faceted ruby from Myanmar was identified as vesuvianite. Photomicrograph by Nathan Renfro; field of view 1.20 mm.

It is a pleasant surprise when a gemologist encounters a vibrantly colored crystal in a gemstone, as most gems are either inclusion free or contain inclusions that are weakly colored due to their small size. When the authors discovered a vibrant yellowish green crystal in a Burmese ruby (see above), it was a very welcome sight. Green crystals in corundum are not common but do occur occasionally. Green spinel and pargasite both occur in gem corundum. The former, a singly refractive mineral, was ruled out immediately because this inclusion behaved as a doubly refractive mineral when examined between crossed polarizers. Doubly refractive pargasite remained a possibility. The surprise came when Raman microspectrometry identified the yellowish green crystal as vesuvianite, also known as idocrase. To the authors’ knowledge, this is the first time vesuvianite has been reported as an inclusion in ruby.

Nathan Renfro is manager of colored stones identification, and John Koivula is analytical microscopist, at GIA in Carlsbad, California.