what is the emerald chemical composition
Emerald has the chemical composition Be3Al2(SiO3)6 and is classified as a cyclosilicate. It has a hexagonal crystal system 6/m2/m2/m. Its density is 2.67-2.78 and it has an index of refraction in the range 1.566 to 1.602. It's hardness is 7.5 to 8 and its streak color is white.