Color : blue, Lightblue,blue-green 
Color of streak : White
Mohs’ hardness : 7.5-8 
Specific gravity : 2.67-2.71
Cleavage : None 
Crystal system : Hexagonal 
Chemical composition : Aluminium beryllium silicate
Refractive index : 1.577-1.583 
Double refraction : -0.006

Aquamarine, together with emerald and beryl, belongs to the beryl group ; it is so named (Latin – Water of the Sea) because of its sea water color. It was also a talisman for sailors. A dark blue is the most desired color. Lower qualities are heated to 752 F / 400 C to change them to the desired aquamarine blue. It is brittle and sensitive to pressure. It is more frequently transparent than emerald. The pigment is iron. Typical inclusions are fine hollow rods which sometimes reflect white light. Where growth lines are present in larger numbers, a cat’s eye effect or even asterism with a six-rayed star is possible. Because of inclusions of foreign substances, physical properties can vary. The maxixe aquamarine from Brazil has quite different constants. It is rarely used any more because the color fades in daylight.