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Being based in a gem centre like Jaipur, GTL is exposed to a range of unusual and bizarre gem materials submitted for identification. Because of the dedication and passion our staff gemmologists possess, these gem materials undergo a thorough research for their complete understanding. The results of such research are shared with the world through publications in various highly read gemmological journals of international repute.

In The Press


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Pradat T. & Choudhary G. (2014) Gem-quality Cr-rich kyanite from India. Gems & Gemology, Vol. 50, No. 1, pp 87-88

In 2009, one of the contributors had the opportunity to see small lots of greenish blue to bluish green Cr-rich kyanite in Jaipur, reportedly mined from the eastern Indian state of Orissa (Odisha). Most of the cabochons and faceted gems, ranging in size up to 25 ct, were highly included. In 2013, this Cr-rich kyanite from Odisha was again available in Jaipur, this time with very few or no eye-visible inclusions. Although a few specimens contained numerous black inclusions (ilmenite), the lack of internal features in most of the stones yielded a more desirable uniform greenish blue to bluish green colour, making them suitable for jewellery mounting.


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Choudhary G. (2014) Yellow sapphire filled with lead glass. Gems & Gemology, Vol. 50, No. 1, pp 92-93

An orangy yellow sapphire filled with lead-glass was examined which appeared hazy throughout, with a roiled effect reminiscent of hessonite; standard gemological properties and microscopic analysis identified the specimen as natural corundum. Numerous low-relief cracks were present throughout the stone with a distinct flash effect along with trapped, flattened gas bubbles, and whitish cloudy patches; these are typically associated with filled stones. The glass-filled fractures appeared orangy yellow against the pale yellow bodycolour of the stone, which also provided it yellow face-up colour. The lead content of the glass was further confirmed by EDXRF analysis.


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Choudhary G. (2013) An ornamental sapphirine - cordierite - sillimanite rock from South India. The Australian Gemmologist, Vol. 25, No. 4, pp 146-151

Seven samples of relatively unknown ornamental sapphirine - cordierite - sillimanite rock was studied, said to be mined from the Karur district of Tamil Nadu, India. Each of the mineral was identified by their characteristic Raman spectra, which otherwise looked similar to quartz with some acicular inclusions. UV-Vis- NIR spectrum revealed the cause of colour in sapphirine to be Fe2+ - Fe3+ charge transfer.


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Choudhary G. (2013) Greenish Blue Spodumene. Gems & Gemology, Vol. 49, No. 4, pp 258-259

Green and yellow colors of spodumene, in addition to the widely known violet-pink variety kunzite, are now familiar to the trade and often submitted to gem labs. Recently, this contributor examined a greenish blue specimen that unexpectedly turned out to be spodumene. The most striking feature of the specimen was its strong pleochroism, which displayed three colors: green, blue, and violet. Absorption spectra revealed the cause of colour to be Mn in various states.


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