14/04/2007

Advanced research for origin identification in unheated sapphires

GRS proudly announces that it has completed an in-depth research program including several thousand samples of sapphires from various mining areas in the Mogok region of Burma (Myanmar). Intensive study of the inclusion properties in sapphires from these different mining areas allows GRS to add more specific geographical origin information. This information includes the mining area within Mogok and future Gemstone Reports will state this result. This progress in GRS Gem Reports comes after detailed research using multiple testing procedures such as analysis of fluid inclusions, solid inclusions, silk patterns, colour-distribution, trace elements, including elements as determined by LIPS and ED-XRF. Various mining areas within Mogok can now be differentiated. This information is used to strengthen our knowledge in differentiating from other newly appearing sapphire sources emerging from origins such as Sri Lanka and Madagascar.

The decline in production in Mogok made fine quality Burmese sapphires very rare relatively to other origins (see figures below and trends over the past years as obtained from our reporting activities). Very deep mining requires higher energy costs at a time of increasing oil prices and international trade sanctions, many mines in Mogok have closed.
Since 2005, large (over 10ct in size) stones have doubled in price. Most large unheated top gem-quality sapphires (including “royal blue varieties”) are now coming from Madagascar and Sri Lanka.
Although cutting style cannot be used for origin identification, many of the Sri Lanka/Madagascar stone are cut in a modified brilliant cut (see sketch). This is used mainly in the Sri Lankan cutting industry in order to enhance brilliancy, save weight from the rough and to improve the overall appearance of the stone. Burmese sapphires with this type of cutting style were rarely observed (see figures below). Based on the availability of sapphire sources in the future, our recommendation for the gemstone market is to consider quality and absence of treatment as a major factor for the evaluation of sapphires (see also increasing trend of no origin reports at GRS).
Please contact GRS concerning any further clarification of our future gemstone reports as well as any further important information. We are pleased to be of assistance to the trade and to the public to the best of our knowledge.

For us at GRS, knowledge and research is only important if shared with the world.

 

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