By the grading step, the grader sits under a good light source and sparates the rough by different tones.
These are the grades, for different stones the use different letters and code for their grades. For colored stones there are many different codes in use depend on company.

The last step, sorting by size, is by eye and scale.
Sometime each stone is weight, for the correct weight category.

     The weight (size) categories are :

•   0.1 - 0.29 gram.
•   0.3 - 0.49 gram.
•   0.5 - 0.99 gram
•   1.0 - 1.49 gram.

•   1.5 - 1.99 gram.
•   2.0 - 2.99 gram.
•   3.0 - 4.99 gram
•   5.0 - over