9 replies to this topic

[bw800402]

I am looking at 2 diamonds that are both 0.87 carats and GIA certified. The vs2 diamond is a very good cut with medium girdle. The vs1 diamond is premium cut with thick to very thick girdle. Other than that they have the same specs across the board. Which one do I want?

[ben]

My own personal preference is to ignore slight differences in clarity or color for more material differences in the stone. I happen to like a nice even correctly-dimensioned girdled, but that's just my humble opinion. Thick girdles hide weight (makes 0.87 stone look smaller) and thin girdles can chip.

[barry]

Tough question to answer without more information.

What is the definition of "premium" and "very Good"?

Two diamonds with the same specs can look entirely different.

[denverappraiser]

Pick the one that's prettiest.

'Premium' and 'Very Good' are not terms that GIA uses to describe cut, or at least they didn't until yesterday (They still don't use premium but very good is the name of one of their middle grades in their new cut grading system that started on 1.3.06). Who graded the cutting and what scale are they using? These terms can mean very different things to different people.

Neil

[bw800402]

According to GIA the first stone is H color vs2 clarity very good polish good symmetry medium girdle with 76.4% depth and 74% table, no fluorescence or culet.

the second is SI1 color F, slightly thick to thick girdle with73.5% depth and 67% table very good polish and good symmetry, slight fluorescence and no culet.

It is an internet dealer so I have yet to see either stone, probably need to do that since what I think will ultimately be most important, but the second stone has its inclusions on the table. The first stone says the the pinpoints are not shown, but it looks like a mark for a crystal or needle imperfection in the center of the table as well. Will vs2 mean that I won't see the imperfections marked on the GIA report and that i will see them on the si1. Will these two grades make a huge difference in noticing the flaws?

[10X]

I am going to assume with those proportions the diamond is a princess? Fancy shapes don't hide inclusions as well as rounds however it depends on the size, nature and location of the inclusion.

GIA does not base a grade on eye-cleanliness. VS2 does not 'guaranee' an eye-clean stone, but overall most VS2's are eye-clean. SI1 clarity stones can also be eye-clean. They can also be eye-visible. Again, it depends on the nature and location of the inclusion.

You should just ask your vendor if the diamonds are eye-clean. Note, eye-clean typically means the inclusion is not visible to the naked eye when viewed at a distance of 10-12 inches

[diamondsbylauren]

Hi Everybody!
bw- I agree with Megan-
Plus, it's useless trying to figure out what imperfections look like by using the plot on a GIA report. The 2 dimensional representaion does not convey so many important aspect of the imperfections. How deep in the diamond are they, for one thing.
But even if they use 3D mapping to plot the imperfections to depth- that still won't tell you if a diamond is eye clean, for example.
It's the darndest thing: Some stones can have a big black booger- even a shape which normally does not hide imperfections well- like an Emerald Cut- and be totally eye clean.
Then you find a VS1 3 carat round where....lookie- YOU CAN SEE THE TEENIE SPECK!
I've seen this- only once, but I have. The stone was a "gem make" ( really really well cut) and it had a really small carbon spot.
GIA was correct to grade VS1 ( in my opinion) Yet, when you looked, you could see the tiny spot.
Here's a large SI2 Emerald Cut

5.21 carats, we graded it to be O-P color and SI2 clarity.
below I've outlined the imperfections



Sometimes SI2 imerfections are really not a bother- even if you can see them.



As Neil pointed out, the term "premium" is not in GIA's vocabulary- so we must assume the seller has assigned names to cuts of the diamonds. t's important to note that many times these terms are more promotional ( sales tools), rather than reality based.

What shape are the diamonds you are considering?

By the way, I think that a good digital photo is essnetial- if the seller can't or won't provide that, it rasies a lot of questions.

[barry]

The advice above from Megan and David is correct.

Judging eye-visibility of inclusions from a plotted diagram is not only meaningless but more critically, misleading.

It's impossible to accurately guage the size, coloration, depth, and/or reflectivity of the inclusion(s). Eye-clean has much to do with the Cut-quality of the diamond. The better the Cut, the less likely that inclusions will be seen in the face-up position. Therefore, you need to be sure that these two diamonds are of similar cut quality, impossible to do just based on a few numbers off the lab report. It is quite possible to have a SI-1 or SI-2 of very good to excellent cut present significantly better and eye-cleaner than a VS-2.

If you can't get to see these two diamonds in person, at a minimum have the vendor work up photos for you, among which should be some with dark-field illumination.

Light performance analyses such as a Gemex Brilliancescope (www.gemex.com)would be excellent.

[bw800402]

The shape of the diamond is princess. .

I have now gotten to look at three diamonds in person. Assuming two diamonds are of equal quality in every respect except one is a 75 pointer with F color, the other is a 90 pointer with H color, which would you prefer? I have looked at both and I like the 90 pointer obviously because it's a bigger diamond but also because it seems to give a better contrast to the size of the diamonds that have been channel set in the ring I've chosen. I looked at an H a few days before and thought it was a beautiful stone but when I was looking at the F next to it I could definitely see a difference. I am tempted to go with the 90 pointer anyway because I don't imagine many circumstances when the ring will be held up to another and scrutinized as closely as I was comparing the F and H. What are the opinions on the matter?

[barry]

I agree. Go with th "H". The fact that to your eyes it has better contrast is your assurance that it will be more readily "seen" in all kinds of lighting environments.

Contrast is a key component of light performance and light performance is what you're buying.