Help buying a used diamond


Jul 15, 2011
Hello, I am new here and this is my first post, so bear with me. I am buying a used diamond, and looking for a little advice. I basically have two questions, bolded below for easy reading since I am probably unnecessarily verbose (first diamond, nervous and babbly, etc).

The first is on the diamond itself. This is the GIA report:

Round Brilliant
Measurements: 6.17 - 6.20 x 3.86 mm

Carat Weight: 0.90 carat
Color Grade: F
Clarity Grade: SI1
Cut Grade: Very Good

Depth: 62.4%
Table: 56%
Crown Angle: 35.5°
Crown Height: 16.0%
Pavilion Angle: 40.8°
Pavilion Depth: 43.0%
Star length: 50%
Lower Half: 80%
Girdle: Medium to Slightly Thick, Faceted
Culet: None

Polish: Good
Symmetry: Very Good
Fluorescence: None

It is currently set in an 18k gold setting with .50 carats of baguettes, but I'm not certain the girlfriend will like the setting, so we may have the stone set in a different setting. She will make the call when we go see it, but we are buying the whole ring regardless. Is $4,250 an acceptable price for that diamond and the setting? If tastes matter at all, she is most concerned with sparkle, so the cut grade was the only thing that I was iffy on. From my research I know GIA won't give an ideal cut rating if polish is only good, but all the other characteristics are within the bounds of an ideal cut. I've read online that polish does not affect the sparkle of a stone that much unless it is fair or poor, though, so I thought it might be a good stone. Is that true, not true, or is it just something we have to see in person?

Speaking of in person, that gets at my second question. The stone, as I mentioned, has a GIA cert, but I obviously want to make sure the ring I'm getting has the same stone in it as the one on the cert. I was planning on meeting at a neutral jeweler's to have them verify the stone. Do I have to go to a special appraiser or someone with special credentials, or since it's already certified can I just go to any diamontologist at any jewelery store (this will be in Philadelphia, btw)? Is this an expensive process on the order of an appraisal, or is this just a glance under a loupe and a, "Yup, on your way, sir"? Basically, I'm looking for advice on how to actually transact the purchase of a used diamond, while being as paranoid as possible. I have no reason to be, in fact he seems to want to cover his bases as much as I do, suggesting we meet at a bank to perform the transaction. I just want to be as cautious as possible, just to be on the safe side.

Anyway, thanks in advance for your help. This site is a great resource - I was pumped when I found it!


Jun 29, 2011
I don't really have much advice, but I'll say, my "used" diamond search is going not that well. I found "the one" but the seller wants to sell it for a teeny tiny discount off of retail. Sigh.


Apr 4, 2010
I just did a search on PS and found 0.90 F/SI1 GIA diamonds for 4100-6500. So I don't think you are really /saving/ by going the used route, especially since you will have to factor in fees for mounting the diamond in the new setting/etc.


Jul 21, 2004
I"m a pretty big fan of using professional appraisal services in order to get a professional service. There ARE capable gemologists who work in and even own jewelry stores but this is decidedly NOT a neutral question since one of the critical questions is whether or not you can do better buying something from THEM. It's also worth noting that far less than all workers in jewelery stores are capable for this job, and this includes the majority of those who call themselves 'diamondologists'.


Feb 27, 2007
Does the GIA certificate include the illustrations that show inclusions? You can maybe confirm it is the same stone by doing that but I would take it somewhere else to get it appraised. Good luck!


Nov 27, 2007
I have an antique diamond with "good" polish. You can see the polish lines with the naked eye if you look close and have very good closeup vision. It is a similar look to heavy surface graining. With my stone it's not all over but on certain facets you can see it more. It's pretty subtle but definitely naked-eye visible. Personally it doesn't bother me on an antique stone but for some reason I think I'd be less forgiving of that effect in a modern stone.

It could possibly be visible on this stone too if you have nearsighted vision like I do.
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