Demantoid is one of the gem varieties of the garnet mineral, andradite. The formula is: Ca3 Fe2 Si3 O12.
In the 2009 a new deposit has been found in Madagascar. North of Ambanja,in front of the Nosy Comba island near the village of Antetezambato.
Most of these stones has a green to green-yellowish colors, the dispersion is very high, therefore are very beautiful in any light conditions with high luster. Small inclusions may be seen only with a loupe.