Hot take: GIA's Excellent cut grade is nearly meaningless and nobody talks about it

I know this will get me ratio'd but hear me out.

GIA grades cut as Excellent, Very Good, Good, Fair, Poor. About 55% of all GIA-graded round brilliants receive Excellent. More than half. For a grade that supposedly represents the top tier of cut quality, that's an enormous range.

Within Excellent, you can have a stone with a 40.6° pavilion and a 34.5° crown — ideal by most measures — sitting next to a stone with a 40.2° pavilion and a 35.8° crown that sparkles completely differently. Both are "Excellent."

GIA's cut grade was always intended as a broad filter, not a precision tool. The diamond industry — and especially online retailers — has turned it into a marketing promise it was never designed to deliver. "GIA Excellent" has become shorthand for "buy this without thinking" which is exactly backwards from how you should be buying a diamond.

Actual cut quality requires looking at the actual proportions on the cert. Table %, depth %, pavilion angle, crown angle, girdle thickness. "Excellent" tells you you're in the right neighborhood. That's all.

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u/farzanahasan2h ago

This is correct and it's something I say constantly. "GIA Excellent" eliminates the disasters — stones with terrible light return, fisheye effects, nailheads. It doesn't identify the best performers within the grade. For that you need to filter by pavilion angle 40.6-40.9°, crown angle 34.0-35.0°, table 54-58%, total depth 59-62.5%. That's where the real cut optimization happens.

u/Marcus_Webb2h ago

The 55% stat is the key. If the majority of stones pass your filter, it's not really a filter. GIA knows this. They've never tightened the criteria because doing so would upset the economics of the industry — too many existing stones would drop to Very Good and lose value overnight.

u/gemvenkat2h ago

The practical advice buried in this is: when you see "GIA Excellent," treat it as the minimum requirement, not the purchase decision. Then go read the actual proportions. 99% of buyers don't do this step and the industry profits from that ignorance.

u/EmmaWatts_UK2h ago

I disagree that it's "meaningless." Going from Good/Fair to Excellent is a genuine quality jump that most people can see in person. But within Excellent, yes, the spread is huge and most consumers don't know that. The grade does its job at the bottom end and falls apart at the top end.

u/anilpandav19932h ago

Hearts and Arrows is essentially the industry's attempt to solve this problem — it's a sub-grade of Excellent that indicates optical precision. But even H&A isn't standardized between labs. GIA doesn't issue an H&A grade. It's just a scope image attached to the cert. So we've solved a problem with another unregulated claim.