Demantoïd

Since February 2009, Madagascar is producing Demantoïd. Some astonishing specimens have been mined as well as gemstones of very fine quality. The mine is situated in the northern part of Madagascar near the city of Ambanja. 

Mostly the stones are found in small size and poor clarity. The colour vary from brown to brownish green, to green and in the ideal case to bluish green. 

 

 

Demantoïd - technical  sheet

OriginMadagascar, Russia, Iran, Namibia, Italy
Chemical Composition CaFe2(SiO2)3
 Refractive Index
 1.888 (+0.007, -0.033)
 Birifrangence none
 Mohs hardness
 6.5 - 7
 Density 3.84 (+/- 0.03)
 Dispersion 0.57
 Crystal structure
 cubic
 Color brownish green, to green to bluish green

 Most of the production would produce stones below a carat. Fine quality stones with a good emerald green color over 2 carats are rare, more than 3 carats are extremely rare.

G. Pocobelli owns a mining permit of demantoïd through a Malagasy partner.

 

 
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