Emerald
Chemical Formula	Be3Al2(SiO3)6
Species	Silicates
Crystal System	Hexagonal
Mohs Scale	7.5-8
Specific Gravity	2.76
Color	Green shades
Streak	White
Luster	Vitreous
Refractive Index	nω = 1.564–1.595,nε = 1.568–1.602
Diaphaneity	Transparent to opaque
Cleavage	Imperfect on the
Fracture	Conchoidal
Crystal Habit：Massive to well Crystalline