Chrysoberyl

 
Color : Golden yellow, green-yellow, brown 
Color of streak: White

Mohsí hardness : 8.5
Specific gravity : 3.70-3.72   
Cleavage : Imperfect 
Fracture: Weak ; conchoidal 
Crystal system : Orthorhombic
Chemical composition : Beryllium aluminium oxide
Refractive index : +0.011 
Flourescence : Usually none; green : weak ; dark red

Chrysoberyl has been known since very early times. Today the varieties alexandrite and chrysoberyl catís eye are especially valued. Deposits of chrysoberyl catís eye are especially found in Brazil (Minas Gerias, Minas Novas) and Sri Lanka ; also in Upper Burma, Malagasy Republic, Rhodesia and Russia (Urals). Stones are fashioned mainly in emerald, Ceylon and brilliant cuts. The famous Hope chrysoberyl, a light green stone of 45ct is completely clean.