•  Sorting by quality (select clean goods & reject included material)
•  Grading (separate in different tones, like AAA, AA, A, B, B+)
•  Sorting by size

From a mine-run only about 5-30% can be used in these
different grades and depend on where the goods are mined.

These processing steps require a lot knowledge
and practice.
In some part of the world rough gems are processed well,
than in others. For most of the African material the
processing in done in Thailand and India.
By some rough, like Brazilian Amethyst and Citrine,
before this steps can take place, the rough have
to be knocked and sawed.