24/04/2016

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 […]

Alerts, News
14/09/2015

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
22/05/2015

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 […]

Alerts, News
22/12/2014

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 […]

Alerts, News
06/11/2013

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 […]

Alerts, News
19/12/2011

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 […]

Alerts, News