Choudhary G. (2007) Glass masquerading as ulexite, Midlands Focus, 11th issue, pp 5 -6

A green sphere, approximately 5.5 cm in diameter with a strong chatoyant band and purporting to be Ulexite, was bought into the Gem Testing Laboratory of Jaipur, India by a sphere collector, also a gemmologist. The sphere had been purchased as synthetic ulexite by the depositor who wanted us to have a look at the specimen in order to provide information on this new and interesting material. The gemmological properties identified the sphere as chatoyant glass

Choudhary G. & Golecha C. (2007) Synthetic star sapphire with hexagonal features, Gems & Gemology, Vol. 43, No. 2, pp 177 – 178

Hexagonal color/growth zoning is a classic identifying feature for natural corundum. However, at the Gem Testing Laboratory in Jaipur, India, we encountered a synthetic star sapphire with hexagonal zoning. Our initial examination indicated that the sample was a natural sapphire with a diffusion-induced star, as suggested by the wavy appearance of the rays and the presence of “silk” inclusions. When the cabochon was viewed from the back, however, we were surprised to discover numerous tiny whitish pinpoints (likely gas bubbles) arranged in curved clouds. When the stone was viewed in immersion with diffused illumination, curved color bands also became apparent. These features are diagnostic of a flame-fusion synthetic origin. This was the first time we observed both hexagonal zoning and curved color bands in a single sample. It provides an important reminder that a gemmologist should avoid making identification without considering all of the evidence presented by a sample. If this stone had been mounted in a closed-back setting, it would have been very difficult to make a correct identification

Choudhary G. (2007) Glass object with circular bands, Gems & Gemology, Vol. 43, No. 2, pp 174 – 175

We received an approximately 188 ct colourless specimen in the shape of a “Shivling,” which is the symbol representing Lord Shiva in Hindu theology. Our initial observation included the use of fiber-optic lighting to look for tell-tale signs of glass, such as gas bubbles or swirls. The most conspicuous feature was a curved zone of whitish bands visible through the base of the object; these bands resembled the curved striae seen in flame-fusion synthetic sapphire. However, the specimen had a lighter heft than would be expected for that material. When viewed from the side (in a direction perpendicular to the axis of curvature of the whitish bands), straight parallel lines were seen. At higher magnification, the curved bands appeared to be composed of planes of white pinpoint inclusions.

Choudhary G. & Golecha C. (2007) Emerald with unusual growth features, Gems & Gemology, Vol. 43, No. 1, pp 66- 68

The Gem Testing Laboratory, Jaipur, India, received a 4.77 ct emerald for identification. When viewed with the polariscope, it exhibited strong strain patterns with patches of color in the optic axis direction. When examined the stone with crossed polarizers while immersed in bromoform, it revealed a mosaic pattern.  In plane-polarized light, these features appeared to be formed by the boundaries of intergrown columnar hexagonal subcrystals. In diffuse illumination (still in immersion), the hexagonal columns appeared slightly darker green than the interstitial areas and could be seen extending throughout the stone. Wavy growth features were seen in a direction perpendicular to the optic axis; the patterns were similar to the chevron-like growth zoning that is typically seen in synthetic emerald, and are indicative of disturbed or rapid growth. The emerald was identified as natural on the basis of overall inclusion pattern and FTIR spectrum.