Choudhary G. (2008) Aventurine K-Feldspar, Journal of Gems & Gemology , Issue 3, pp 20-22(In Chinese with English abstract)

The Gem Testing Laboratory of Jaipur, India encountered few aventurine feldspars which were proved belonging to the ‘potassium feldspar’ rather than the oligoclase (sunstone). The samples studied did appeared to be sunstone feldspars as they readily displayed aventurescence, however physical, optical and chemical properties did not match to those of sunstone but to those of potassium feldspar. The overall features of these specimens were consistent to those of orthoclase feldspar. Three specimens- orange brown, pinkish brown and a dark brown were studied; two specimens (orange brown and pinkish brown) were faceted while one was fashioned as a cabochon and displayed four-rayed asterism.

Choudhary G. (2008) Synthetic emerald necklace, Midlands Focus, 13^th issue, pp 5-7

At the Gem Testing Laboratory of Jaipur, the author frequently receives multi-strand necklaces assembled from various types of gemstones including natural, synthetic and treated materials. Recently, an interesting necklace was submitted which consisted of four strings of emerald beads weighing approximately 3,093 carats. The necklace consisted of mixture of synthetic emeralds produced by hydrothermal as well as flux-fusion processes. This was however, presented as natural emeralds.

Choudhary G. & Golecha C. (2007) A remarkably large clinohumite, The Journal of Gemmology, Vol.30, No.5/6, pp 303-306

Recently a remarkably large clinohumite weighing 9.45 ct was identified at the Gem Testing Laboratory, Jaipur, India. This bright brownish-orange specimen of clinohumite was said to be from the Pamir Mountains, Tajikistan. Clinohumite, a rare magnesium silicate, is a monoclinic member of the humite group of minerals and is usually found below three carats. This study reviews the gemmological properties, observations of internal features and IR analysis of the specimen. The colour, its remarkable size and the observed magnification features proved it a collectors’ gem.

Choudhary G. & Golecha C. (2007) Now synthetic beryl simulating “Pariaba” from Tairus, Gems & Gemology, Vol. 43, No. 4, pp 385 -387

At the September 2007 Bangkok Gem & Jewelry Fair, Tairus Created Gems (Novosibirsk, Russia) was selling a gem material they called “Synthetic Paraíba.” A representative informed one of the authors (CG) that it was “Paraíba shade synthetic beryl,” which Tairus had recently introduced into the market. Both crystals (~0.3–0.7 g) and cut specimens (~0.2–1 ct) of the bright greenish blue material were available. The crystal was readily identifiable as a product of hydrothermal growth by the presence of wavy features on its surface. This pattern was expressed in the interior of both samples as (undulating) chevron features, some of which were visible even to the unaided eye. Copper and iron were identified as the cause of the blue colour in these samples.