Research News

Sapphires from the Gem Rush Bemainty area, Ambatondrazaka (Madagascar)

Vincent Pardieu, Wim Vertriest, Vararut Weeramonkhonlert, Victoria Raynaud, Ungkhana Atikarnsakul and Rosey Perkins
February 24, 2017
Sapphire
Sapphires of approximately 15 cts in size, reportedly from the gem rush near Ambatondrazaka, seen at KV Gems office in Bangkok in Dec 2016; stones courtesy KV Gems, Bangkok. Photo by Vincent Pardieu/GIA.

New discoveries of fine quality blue sapphire sizes suitable for large fashioned gems are always welcomed by the gem trade. In the last decade and half, the island of Madagascar has emerged as a globally important source of gem quality corundum. However, the latest find of attractive large stones at Bemainty is problematic for the trade. Although it has produced more fine blue and padparadscha type sapphires than any other recent Malagasy deposit in just a few months, it is located deep inside a designated conservation area where mining is prohibited by the government.

This report describes conditions at the mining sites, the mining methods used, and documents the gems seen at the mines and in local gem markets. It also provides a summary of the recent history of gem corundum mining in Madagascar along with regional and local geological context for the discovery.

As a preliminary study, researchers from GIA’s Bangkok laboratory analyzed 38 representative Bemainty sapphire samples obtained from a reputable merchant in November 2016. They investigated gemological properties, inclusion scenes, spectroscopic features, and trace element chemical composition. Results from their study and field observations from the mining area appear in a new article titled “Sapphires from the gem rush Bemainty area, Ambatondrazaka (Madagascar).”
 
This study indicates that the geographical origin of stones from this new locality will be challenging for gem labs to determine as the material ranges from geuda-type stones with low iron content similar to those from other Malagasy deposits and Sri Lanka, to gems with higher iron content resembling some blue sapphires from Myanmar or Tanzania.

The new sapphire find at Bemainty is east of Ambatondrazaka and falls inside the Ankeniheny-Zahamena Corridor (CAZ), which was designated a protected area by the Malagasy government. As mining is prohibited within the CAZ, the arrival of thousands of people determined to mine challenges conservation efforts by the authorities.

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