Observation is an essential moment in the choice of a diamond. The diamonds are evaluated after being observed with the magnifying glass X10, the microscope then confirming the observations made with the magnifying glass. The defects are due to the shape of the original rough diamond, the inclusions or the mistakes of the diamond cutter.
% Of proportion of the table
Observe the curves that fit slightly inside the table.
Ideal is between 54% and 59%.
Observe the table
Rotate the diamond to observe a ray of light on the table and see the outlines.
The depth of the pavilion
We see the light due to the depth of the breech in the center of the table. It should ideally make 1/3 of the table (Reflection Table). Must have neither a spot of light too wide nor a point too small.
A good thickness of the girdle is important for the appearance and for a nice play of light.
A too thin girdle will be difficult to crimp, while a too thick one will present a useless overweight, a poor refraction of light and a lack of aestheticism.
Ideal: thin, medium to slightly thick
GIA Excellent Cut
Proportion Values and Ranges:
Table size: 52% to 62%
Depth percentage: 58.1% to 63.6%
Pavilion angle (Main): 40.6° to 41.8°
Crown angle (Bezel): 31.5° to 36.5°
Lower girdle halves: 70% to 85%
Star length: 45% to 65%
Girdle (min/Max): Thin to Slightly Thick
Culet: None to Small