Choudhary G. (2012) Dioptase from Mozambique, The Australian Gemmologist, Vol. 24, No.9, pp 215-219
One dark bluish green dioptase specimen weighing 8.88 carats was submitted to the Gem Testing Laboratory, Jaipur, India. The specimen was unusual for its size, crystal form, transparency and phantom-like growth. Dioptase, usually found as massive aggregates and druses on other minerals, was seen here as a single crystal of fairly good size. The specimen was reported to originate from Mozambique. IR spectra obtained by KBr method was very useful in the identification together with its gemmological properties. The specimen was dark bluish green, a colour typically associated with translucent emeralds exhibited under normal lighting/viewing conditions. However, under transmitted light, it displayed a much brighter green colour and a better degree of diaphaneity. IR spectra measured by KBr method displayed strikingly clear and distinct peaks in the region 4000 - 400cm-1. Major peaks were seen at around 3380 and 3260 cm-1 due to O-H vibrations; 1735, 1265, 1120, 993, 956, 887 and 781 cm-1 due to Si-O stretching; 628, 572, 516, 495 and 450 cm-1 due to Si-O bending
Download PDF