Aquamarine is a beryl, the same family as emerald.
It is said that its calming energies reduce stress and calm the mind. Aquamarine has an affinity with sensitive people, and is a stone of courage. 
Approx 4x2cm 
Colour: Blue

Luster: Vitreous

Birthstone zodiac sign: Pisces 

Associated month: March

Chemical formula: Be₃Al₂SiO₆

Hardness (Mohs hardness scale): 7.5 – 8