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Advise Needed For 0.8Ct I-Si1 Excellent Cut Round Brilliant Diamond Please?


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This is my first post and I have been following the forum for some time.


I'm looking to buy an 0.8ct diamond for a while. I have recently found this online. It was certified by GIA back in 2004 so it doesn't have a cut grade (?), the vendor told me it is excellent cut. The ideal scope and Sarin report are as follow :-






The price quoted is $3110, the HCA score is 2.3. It only score very good in all criteria. Should I buy this? I really appreciate all the helps! Thanks!

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Diamonds graded by GIA prior to Jan 2006 don't have a cut grade. However, the information provided by the vendor more than compensates for the lack of it (in my view). It seems a nicely cut diamond, and the price is reasonable - at the top of the market for similar stones when shopped online, but you are getting more info and better service than from many other internet advertisers.


There seems to be some leakage under the table and on the bottom crown facets of the IS image, but it may be because the diamond (or the camera) weren't perfectly straight and in axis with each other. If you can see the diamond, you should be able to check that there are no dark or windowed areas just under the table. The Sarin scan has an anomaly in the girdle - possibly someone bumped into the scanner when it was reading - ask the vendor if he can retake it if it worries you.


The HCA is frankly irrelevant at this point - you have far more information available through the scan and the IS image.


Should you buy this? If you are shopping for a 0.8x I/SI1, it's a perfectly reasonable candidate, subject to two conditions:


1. Clarity. There is nothing apparent in the IS image, but it isn't taken with the goal of showing inclusions. Ask the vendor, and ask him to take photos if you aren't convinced.


2. Why is the report so old? Has the diamond been set and then unset? Has it suffered any damage since? I would close the deal conditional on the diamond getting a clean bill of health from an expert of your choice.


ETA: you can plug the Sarin values into the GIA cut grade estimator at https://www.gia.edu/facetware (it is indeed an "excellent"), disregarding the "16%" girdle reading.

Edited by davidelevi
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Thanks David, I was wondering about the old report as well. I asked the vendor whether the diamond can be re-certified but they said it will be up to me to submit it to GIA once I bought the diamond.


I have been using HCA score to determine my seach for diamonds so far... am I doing it the wrong way round? If this diamond only scored very good in all criteria, does it mean that it will be less sparkly than a diamond that scored all excellent? From the look of the IS, would you be able to tell whether it display 'Hearts and Arrows' pattern?


As for clarity, I have been reassured that it is eye clean.


Thanks for your help.

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The HCA - with all its limitations (and they are quite a few) has been developed from the start as a "reject" tool, not a "pick" tool. In other words, it's a sieve to eliminate poorly cut diamonds, not to find well cut ones. It was also developed (and never changed since) in a world where the amount of information available on rounds "by default" was far scarcer than it is today, although it was only 10 years ago. Nowadays, I'd much rather use a GIA or AGS cut grade and information about crown and pavilion angles available on the reports even to screen diamonds out.


As far as "it scored only very good" - Garry Holloway liked a computer-generated ASET image of a highly simplified model of that diamond marginally less than that of another computer generated ASET image. Is that relevant to how the real stone will look to you?


H&A: there is no commonly accepted definition of "H&A", so it would be tough to answer even with an H&A viewer image - which definition do you want to use?


One can see the arrows pretty well in the IS image - and in some cases (the ones at 2 and 4 o'clock) some slight irregularity in their pattern. The most critical view for H&A is that of the hearts, and it is taken with the diamond turned 180° compared to the IS image, so cannot really say what they look like. It seems a nicely cut stone regardless, but if H&A is important to you, ask the vendor to take a shot of the hearts using an H&A viewer.


BTW - the vendor seems to be skirting around the issue with the report date. No-one (not I, certainly) doubts the information on the report as far as size, clarity, colour and finish when the diamond was graded, nor is anyone disputing that it would get an "excellent" cut grade from GIA today, so the problem is not getting it regraded because of that. The questions are:


1. Has the diamond suffered any damage in the 8 years since it was seen by GIA? A chipped culet or girdle could easily send the SI1 to I1. And there is that girdle anomaly on the Sarin (which is not dated, BTW, so it opens up all sorts of possibilities - some totally innocent, and some far less so).


2. Why is the report so old in the first place? It may have been something that someone forgot at the bottom of the safe for 8 years, or it may be something that has been repurchased yesterday with an old report (which is fine, since diamonds don't age, but the risk of damage is much higher in the second case, and some people dislike the idea of getting something "used" - not that they would know if the vendor didn't tell them, but still...)

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Thanks for your advice David, the vendor confirmed that there is no damage to the diamond and the anomaly reading on Sarin may be due to some dust that was on the diamond during the scan? They do not know the history of the diamond as it is their partner's stock. But I have been reassured that it is in top notch condition.


They did mentioned that a feather is located in the crown close to the girdle but they don't think it will affect the durability.

Edited by dlcs
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