Russian Synthetic Ametrine

Abstract

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The 3543 cm^-1 Infrared Absorption Band in Natural and Synthetic Amethyst and Its Value In Identification

“…Photos by V. S. Balitsky. metal mask containing holes of 10-50 mm in diameter. In the latter case, it was possible to grow prismatic crystals that were very similar to natural amethyst in terms of morphology and internal growth structure (Balitsky and Balitskaya, 1985;Balitsky et al, 1999).…”

“…Figure 20. The plates of multicolored synthetic quartz in image A (2.5 mm thick and 6.0 cm tall, sliced parallel to a) were cut from the same crystal, which was grown in an alkaline solution on a seed plate cut parallel to c. The multicolored nature is related to a decrease of oxygen potential in the solution (Balitsky et al, 1999).…”

Synthetic Gem Materials and Simulants in the 1990s

“…There were significant developments in the growth and treatment steps needed to make synthetic ametrine (Balitsky et al, 1999a; figure 19), which has been commercially produced hydrothermally from alkaline solutions since 1994. It can be identified by a combination of characteristics, including twinning and color zoning.…”

Distinction of Natural and Synthetic Ametrine by Microscopic Examination—A Practical Approach

“…The synthetic counterpart is grown hydrothermally from iron-bearing solutions. Commercial production employs seed material consisting mainly of basal quartz plates (Balitsky et al, 1999(Balitsky et al, , 2000(Balitsky et al, , 2001. Iron is incorporated in different forms into the synthetics, resulting in yellow and colourless growth zones in the as-grown crystals.…”

“…The treatment may lighten intense violet r growth zones and turn light violet z growth zones to light yellow (Neumann and Schmetzer, 1984). Although infrared spectroscopy can be an effective tool for distinguishing natural and synthetic amethyst and ametrine (see, e.g., Kitawaki, 2002;Balitsky et al, 2004;Karampelas et al, 2005Karampelas et al, , 2011 and various references therein), microscopic examination will reveal information about twinning, colour zoning and occasionally also about inclusions-features that differ in natural versus synthetic ametrine (Crowningshield et al, 1986;Lu and Shigley, 1998;Balitsky et al, 1999;Notari et al, 2001;Hainschwang, 2009). Because it is a widespread practice in the trade to mix synthetic quartz into parcels of natural amethyst, citrine and ametrine, a simple method for separating these natural quartz varieties from their synthetic counterparts is commercially warranted.…”