Lapidary Cutting Rough Grading Chart

Gem grade flawless / eye clean
Should be able to cut a single larger clean stone from the rough.
May have surface flaws but the interior should be clean.

AA Grade 95% to 100% of the stone is clean usable
This grade usually will require some trimming to produce a clean stone or a single larger stone that may not be eye clean.
Usually 10% less than gem grade stones.

A Grade 90% to 95% of the stone is clean usable
This grade usually will require some trimming to produce a clean stone or a single larger stone that may not be eye clean.
Usually 25% less than gem grade stones.

B grade 75% to 90% of the stone is clean and usable
This grade will require trimming to produce a clean stone or multiple stones.
Usually 50% less than gem grade material.

C grade 75% or less of the stone is clean and usable
This grade will require trimming to produce multiple clean stones or a single large included stone.
Usually 75% less than gem grade stone.

All grading is only the opinion of Silva N Sons.
We don’t guarantee cutting results or weight retention.