The chrysoberyl, not to be confused with beryl, is an aluminate beryllium with formula. BeAl2O4. In the past were called chrysolite, no longer used in the gemological nomenclature.
His hardness (8.5) make it a very durable gem ,the fourth hardest natural gemstone, between corundum and beryl .
This gem it is found mostly in Sri Lanka and Brazil. In this case the stone comes from Brazil and is has some small inclusions; the color is brownish yellow.