Gemstones
Identifying new Kashmir-type sapphires from Madagascar
2017/10/09
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Dr. Adolf Peretti, second from left, looks on as a seminar participant examines a sapphire from Madagascar

GRS GemResearch Swisslab AG is once again fortifying its role in the gemstone industry with a recent study that aims to effectively distinguish sapphires from a new mine in Madagascar from those mined in Kashmir to ensure transparency in the market.


GRS GemResearch Swisslab AG is once again fortifying its role in the gemstone industry with a recent study that aims to effectively distinguish sapphires from a new mine in Madagascar from those mined in Kashmir.

The project, which involves a Master Set of more than 50 reference samples from both mines, will help foster transparency in the trade, according to Dr. Adolf Peretti, founder and CEO of GRS.

“Spectacular inclusion features have been found in sapphires from Bemainty in Madagascar and they resemble textbook Kashmir (from India) sapphire inclusions. As a consequence, a certain degree of misinterpretation of these sapphires seems to exist in the market, and a series of stones from Madagascar has possibly been falsely classified as Kashmir sapphires,” revealed Peretti.

He also cited an unprecedented rise in the price of Kashmir sapphires over the years, reaching more than US$100,000 per carat, while their counterparts from Madagascar are 10 times less expensive.

“This offers a great potential for fraud, and the correct identification is thus an important part of the challenge of internationally recognised gem-testing laboratories,” added the gemstone specialist. 

The new mine was discovered at Bemainty, near Ambatondrazaka and Didy in Madagascar in late 2016. The mining area, which has since been closed, produced a considerable amount of large sapphires, including Padparadscha and yellow sapphires. 

GRS Master Set

The Kashmir Master Set was prepared from GRS’ reference collection of hundreds of sapphire samples from Kashmir. The Ambatondrazaka Master Set, meanwhile, includes samples from independent agents that GRS sent to the new mines, and cut and polished stones from more than five reliable sources. 

The study compared the following properties: Solid and fluid inclusions, age of zircon inclusions, colour zoning, inclusion features indicative of Kashmir sapphires, and UV-fluorescence analysis.

GRS revealed that, among other findings, Kashmir sapphires contain a special type of pseudo-secondary fluid inclusion features, which are largely absent stones from the new Madagascar mine.

Isolated yellow colour zones were also found in samples from the new mine, which are not present in Kashmir sapphires. 

“Based on our Master Sets, we can confirm that comparing the minute details of the sapphires makes it possible to distinguish the two origins. Re-checking is recommended for sapphires in the market between 2016 and 2017, which are claimed to be from Kashmir,” noted Peretti.
 

Tag: #Sapphires
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