Natural Aquamarine 13.33 ct certified

An ALGT Antwerp cetified Aquamarine (Natural Beryl) of 13.33 ct
ALGT COLORED STONE IDENTIFICATION REPORT
IDENTIFICATION
Species .................................................................................... Natural Beryl
Variety ....................................................................................... Aquamarine
DESCRIPTION
Shape & Cutting Style ...................... Modified Octagon, Step Cut
Measurements ............................................ 17.08 x 13.50 x 7.89 mm
Carat Weight ........................................................................... 13.33 Carat
Color .......................................................................................................... Blue
Transparency ......................................................................... Transparent
ADDITIONAL GRADING CHARACTERISTICS
Color Quality Grade ................................................. Fine Color Quality
COMMENTS
Aquamarine is commonly heated to improve its color.
There is currently no scientific method available to
determine whether this gemstone has been enhanced or
not. 

MAIN PROPERTIES OF AQUAMARINE
Chemical Composition ................................................. Be3Al2(SiO3)6
Crystal System ..................................................................... Hexagonal
Mohs Hardness ........................................................................ 7.5 - 8.0
Specific Gravity ..................................................... 2.62 - 2.80 g/cm3
Optical Character .................................................................... UniaxialRefractive Index ............................................................ 1.560 - 1.602
Birefringence ................................................................... 0.004 - 0.007