The infrared spectrum of the unmounted specimen, with peaks at 1037, 462, 443, and 430 cm –1, confirmed the material was glass. These properties, along with electron microprobe analysis, indicated that the two samples were not diaspore or any other natural material, but rather man-made glass. A series of absorption lines related to rare earth elements (REE) were observed by a handheld prism spectroscope. Facet junctions were generally smooth, with small chips. The specimens were fairly clean, with no obvious inclusions and no obvious scratches on the surface. Both samples were yellowish green in fluorescent light with a color temperature of 5500 K (figure 1, left) and brownish yellow in incandescent light (figure 1, right). The material was reportedly purchased from Turkey as Zultanite, a designation the client wished to confirm. The Gemological Institute of China University of Geosciences in Beijing recently received two samples, an unmounted 8.44 ct 10 × 12 mm faceted pear-shaped specimen and a ring with an 8 × 10 mm faceted oval, that displayed a color-change effect. Akgun, “Zultanite, or colour-change diaspore from the Milas (Mugla) region, Turkey,” Australian Gemmologist, Vol. Zultanite has only been found in the Anatolian Mountains of Turkey (M. Zultanite is the trade name of diaspore that exhibits a color-change effect the material appears yellow, pink, or green in different light sources. Hatipoglu et al., “Gem-quality transparent diaspore (zultanite) in bauxite deposits of the Ilbir Mountains, Menderes Massif, SW Turkey,” Mineralium Deposita, Vol. However, gem-quality transparent diaspore is rare and appears to be unique to the Ilbir Mountains area in southwest Turkey (M. Pardieu, “ Hunting for ‘Jedi’ spinel,” Spring 2014 G&G, pp. 1–18), and usually appears as a mineral inclusion in sapphire, ruby, and spinel (V. Abedini, “Geochemical investigations on Permo-Triassic bauxite horizon at Kanisheeteh, east of Bukan, West-Azarbaidjan, Iran,” Journal of Geochemical Exploration, Vol. Photos by Xiaoyan Yu.ĭiaspore, a relatively common mineral with the chemical formula AlO(OH), is found in metamorphic bauxite deposits (A.A. The color-change effect is apparent when switching between the two illumination types. These glass imitations of Zultanite are shown in fluorescent (left) and incandescent light (right). Comprehensive CAD/CAM For Jewelry Certificateįigure 1.
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