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Importance of symmetry in princess cut.


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I am a first-time diamond buyer and am looking to purchase a princess cut diamond. I was wondering what the noticeable (to the naked eye) difference is between a Good symmetry grade and a Very Good grade (graded by GIA), all else being equal. For example, in a diamond in the ideal range for depth and table, how important is it to get Very Good symmetry as opposed to Good symmetry?


Thank you.

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You won't see the difference.


I have attached a graphic showing "Symmetry". The "meet" points of the junction lines between the top to the bottom of the stone dictate the Symmetry grading.


The differential between Very Good to Good is microscopic and nothing that you or anyone looking at the diamond would be able to pick up.


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Thanks a lot for the reply!


These are 2 diamonds that I've been looking at, both Princess:



Carat Weight: 1.86

Shape: Princess

Length-to-Width: 7.17 x 6.88 x 4.61

Color Grade: I

Clarity Grade: VVS1

Depth: 67%

Table: 67%

Symmetry: Good

Polish: Excellent

Girdle: TN-STK

Culet: NON

Fluorescence: NON

Report: GIA

Price: $9900



Carat weight: 1.54

Cut: Signature Princess

Color: I

Clarity: VS2

Depth %: 64.9%

Table %: 71%

Symmetry: Very good

Polish: Excellent

Girdle: Medium to slightly thick

Culet: None

Fluorescence: None

Measurements: 6.56x6.52x4.23 mm

Crown height: 8.6%

Length/width ratio: 1.01

Report: GIA and GCAL

Price: $8900


In terms of differences, obviously the first one has the bigger carat weight and the higher clarity. The second has the slightly higher symmetry, but based on your response, this isn't an issue. I am still working on getting the Crown height for the first.


But based on these numbers, are there any red flags for either of these? Which one would you prefer?


Thanks a lot!

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The best measurement I have found and use is the Brilliancescope by Gemex Systems.


Doesn't sound as if the Vendor you're dealing with has this machine.


Can he at least send you comparison photo's of these two diamonds?

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I do not agree that its's typical to have to "go blind" with an internet vendor.


Good digital photos should give you a pretty good idea of the personality of the diamond.

Barry uses the B-Scope, I do not- but both he and I send accurate photos to people. As do other sellers.


It's obviously more difficult for a vendor to do this if they do not have the diamond in hand.

Then they are in the same position as all the other people trying to judge a diamond by numbers alone.

The blind leading the blind.

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Sometimes GCAL gives some pretty good cut information but they have several different reports that they issue depending on what the client orders. Read the details on that report and see if it says anything more than the GIA report. I'm with both of the above, there's not really enough information presented to give you advice. If they are from the same vendor and you've got enough limit on your credit card, you may be able to buy them both, compare them side by in a variety of lighting environments and then return one of them.

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I beg to differ slightly from Barry's opinion. In my experience, many princess cuts with "good" symmetry have had a noticeably off-center culet. This makes the stone look squewed. Obviously, getting pictures of the diamond beforehand should eliminate this concern. Princess cuts with VG or EX symmetry rarely suffer from this problem.


From these numbers, there are no obvious red flags, but I would make sure there is a comfortable return policy from your vendor, just in case you don't like it when you see it.


Good Luck


I'd like to extend a warm welcome to David from Diamonds by Lauren.

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Thank you George!


ON this issue, though, I agree with Barry.

I can't recall seeing a princess cut diamond which GIA graded "Good" symmetry which had the culet noticably off center.


On the other hand, I have seen Princess Cuts which GIA gave VG, or EX in symmetry that were....well not too pretty.

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