Aquamarine

Aquamarine, and Emerald belong to the beryl group. It is named (latin - Water of the Sea) because of its sea water color. It was a talisman for sailors. The dark blue aquamarine is the most desired color. Lower qualities are heated to 752F/400C to change them to the desired blue. The aquamarine is very brittle, and susceptible to pressure. It's more transparent than emerald, and its pigment is iron. Typical inclusions are fine hollow rods which sometimes reflect light. When there are growths in large numbers, it can give a cat's eye effect, or even asterism with a six-rayed star.

• Color : Light blue, blue, blue-green
• Color of streak : White
• Mohs' hardness : 7 1/2-8
• Specific gravity : 2.67-2.71
• Cleavage : None
• Fracture : Conhodial, uneven, brittle
• Crystal system : Hexagonal (triangonal); long prisms
• Chemical composition : Al2Be3(Si6O18) aluminum beryllium silicate
• Transparency : Transparent to opaque
• Refractive index : 1.577-1.583
• Double refraction : -0.006
• Dispersion : 0.014
• Pleochroism : Definite, nearly colorless-light blue
  Blue: sky blue
• Absorption spectrum : 5370, 4560, 4270
• Maxixe-aqua : 6540, 6280, 6150, 5820, 5500
• Fluorescence : None