Choudhary G. & Golecha C. (2006) Trapiche – the fixed star, Gems & Jewellery, December 2006, pp 122-123

Trapiche emeralds are very rare, and when colour and clarity are good, this feature puts them into the most desirable class of gemstones. Recently, we had the opportunity to examine a suite of four such trapiche emeralds, said to be cut from the single crystal, courtesy of Birla Enterprises. The spoke-like 'rays' emanating from a hexagonal centre give an appearance of a fixed six-rayed star and the cores may be green, white, colourless or black.

Choudhary G. & Vyas M.B. (2006) Natural sapphire with unusual inclusions, Gems & Gemology, Vol. 42, No. 2, pp 179 - 180

A 3.56 carat blue stone was identified as natural sapphire. With magnification, the stone displayed some unusual inclusion patterns. Long, parallel needle-like inclusions with some curved bends were present, along with long, slightly wavy fibre- or needle-like structures. The visual appearance of both was similar to etch channels. Additionally, the stone contained a reddish brown to white inclusion, with a hexagonal cross section, that resembled a hockey stick. It gave impression of a hollow tube filled with foreign material

Choudhary G. (2006) Two unusual star emeralds, Gems & Gemology, Vol. 42, No. 2, pp 171-172

The author examined two fine bright green emeralds that showed asterism. Both displayed a weak (though distinct) six-rayed star, with the strongest ray aligned parallel to the length of the stone. Observation of both specimens with magnification and strong fibre optic lighting revealed minute iridescent inclusions in abundance. At higher magnification, these inclusions appeared to be hexagonal and triangular discs or platelets; some were elongated as well, similar to knife-shaped rutile silk in corundum. The inclusions were seen to form cloudy planes that were mainly oriented perpendicular to the c-axis. Careful examination showed that the inclusions within the planes were roughly aligned in three directions that intersected at approximately 60^o.  These orientations are similar to those observed in star corundum.

Choudhary G. (2006) Sapphire with unusual colour zoning, Gems & Gemology, Vol. 42, No.1, pp 74-75

The Gem Testing Laboratory Jaipur encountered an 11.29 ct sapphire with unusual colour zoning. The stone had been faceted with a large flat area on the pavilion, and the reasons for this were quickly apparent. When the sapphire was viewed table up, it appeared almost colourless, with a strong blue colour zone concentrated on the large pavilion surface. Although strong colour zoning evoked suspicions of diffusion treatment, the absence of colour concentrations along the facet or girdle edges, and pattern of the colour zones and their location along only one side of the sample eliminated this possibility