AQUAMARINE
VARIETY OF: Beryl , Be3 Al2 Si6 O18 .
USES: Gemstone.
BIRTHSTONE FOR: March
COLOR: various shades of blue to blue-green.
INDEX OF REFRACTION: 1.57 - 1.60
BIREFRINGENCE: 0.004 - 0.008
HARDNESS: 7.5 - 8