Colored stone guides
Gemstone Quality Grades
Calibrated colored stones are sold against a single quality word instead of separate color and clarity grades. Here is what that word carries.
The scale
Commercial through AAA
Calibrated stones — cut to standard millimeter sizes for setting, rather than as one-off individual gems — run from Commercial at the everyday end through B, A and AA to AAA at the top.
What the word is doing
One judgment, three things
It bundles color, clarity and cutting quality into a single word. That is both its usefulness and its limitation: it tells you where a stone sits overall, and it does not tell you which of the three is carrying it. An AA stone might have excellent color and ordinary clarity, or the reverse.
The important caveat
A supplier's scale, not a laboratory's
Unlike the D-Z scale, these letters are not defined by an independent body and they are not standardized across the trade — one supplier's AA is not guaranteed to match another's. Read it as a reliable ranking within a single supplier's stock rather than as a universal grade.
Where you will see it
Calibrated stones only
One-of-a-kind stones are described individually instead, with their own color, clarity and certificate where they have one — so a unique stone carries no letter grade, and filtering to a grade will not show it. Lab-grown calibrated stones are described as eye-clean rather than on this ladder, and diamonds use their own grades entirely — see diamond clarity and diamond color.