New types of synthetic periclase identified by C2S inclusions – dicalcium silicate cement hardener

Naturally occurring periclase is a relatively common mineral phase. Due to its small crystal sizes, it never gained recognition in the gem-industry in terms of commercial importance. Synthetic periclase is commonly used for technological applications and is available in large quantities and sizes (Joachin et al., 2012). In the past, synthetic periclase was marketed in […]

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Warning: Synthetic Padparadscha sold as Natural in the trade.

During testing at GRS we have encountered an orangy-pink sapphire reminiscent of heated padparadscha. An 8.60 ct example was identified as synthetic during high-tech testing, identified as containing Cr and Ni concentrations, and a broad infrared band around 3000 cm-1. Although the customer was informed of the stone being synthetic, it might be possible that […]

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GRS Alert: Unusual phosphorescent pebbles identified as synthetic aggregates

Phosphorescent pebbles are presented in the market as natural rounded pebbles (3.53 density) possessing extraordinary properties such as green phosphorescence when exposed to a strong light source and patchy blue to green fluorescence in short- and long wave UV-light (Figure 1), again with green phosphorescence (no blue). Such items appeared multiple times in the last […]

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GRS Alert: A new type of synthetic spinel appears at the Bangkok show

Introduction In May 2015, the author (AP) was made aware that a company in Thailand (Tairus Co. LTD, Bangkok) had commissioned to a laboratory in Russia the production of new types of synthetic spinel of “lavender” colors by the method of crystal pulling from flux. This technique is the same used at the Institute of […]

Alerts, News, Spinel

GRS Alert: New spinel treatment discovered involving heat- and cobalt-diffusion

Introduction Cobalt-spinels are considered one of the most precious spinel and are rarely colored blue with or without grey to black tones. Blue Cobalt spinel are at least 10-100x more expensive per carat than grayish-blue colored spinel. Cobalt intensifies the blue color in spinel, considerably enhancing its beauty. Cobalt-spinel over 5ct can be 10,000 to […]

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GRS Alert: Warming of Mozambique rubies previously certified as unheated by GRS

We would like to inform our customers that rubies found to be unheated when tested by GRS are sometimes heated after certification and presented as natural unheated rubies to the market without re-certifying with GRS. This very low temperature warming does not require repolishing of the stone and therefore no weight loss and no dimension […]

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GRS Alert: Next-generation of synthetic diamonds reach market

CVD-grown Blue Diamonds – Identified by GRS and CGL-GRS laboratories Hong Kong, Lucerne and Vancouver – A distinctly new type of synthetic blue diamond sized from 0.25 carats to over 1.25 carats turned up at both the Bangkok and Hong Kong Gems & Jewellery Fairs in September 2013 along with pink, yellow, and colourless varieties of […]

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New generation of diffusion-treated sapphire appear in large numbers on the market

A large number of diffusion-treated stones are detected in the laboratory. The diffusion-treatment includes the well-known method of adding Titanium in the surface. Some of the material has been additionally Beryllium-treated. The new aspect of this treatment is that the treaters obviously select already heat-treated sapphire with internal blue color-zoning. Than the stones are diffusion-treated […]

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GRS Alert: Clarity enhancement of rubies with a foreign solid filler including Bismuth

By Dr. A. Peretti and W. Bieri For the last couple of years, the appearance of lead-glass treated rubies has been widely recognized in the trade. The treatment is primarily used to enhance clarity in rubies or pink sapphires of lower commercial value. This treatment has been regularly seen at the GRS laboratory in rubies […]

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