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GIA Grading of my Diamond Pick G

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joelcoqui

Rough_Rock
Joined
Sep 17, 2015
Messages
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I found a round stone that has Excellent polish and Excellent symmetry but the cut is just Good. My main question is... If the symmetry is Excellent I dont understand why the Good rating for the cut. Isnt the cut grade and symmetry suppose to be similar? The diamond is lovely though- with a G color and has Slight Inclusions. Please explain. 1.28 ct. Do you have a price range that this stone should be in?
 
joelcoqui|1442493524|3928773 said:
I found a round stone that has Excellent polish and Excellent symmetry but the cut is just Good. My main question is... If the symmetry is Excellent I dont understand why the Good rating for the cut. Isnt the cut grade and symmetry suppose to be similar? The diamond is lovely though- with a G color and has Slight Inclusions. Please explain. 1.28 ct. Do you have a price range that this stone should be in?
Click to expand...

Symmetry has to do with the roundness of the stone and the symmetry of the placement of the facets. Cut has to do with the
table size, depth, crown and pavilion angles and how well they complement each other.

Can you post the table size, depth, crown and pavilion angles and we can probably figure out why it only got a good.

The other thing you could do is use those values and run it through the HCA tool which will give you an idea of where your stone
may be lacking (or not).
https://www.pricescope.com/tools/hca
 
There are some stones which are not GIA excellent and yet can score better on the HCA and get AGS Ideals. For example stones with Pavillion angle less than 40.6 coupled with a steeper crown. However these are much rarer

There can be beautiful stones which are not GIA excellents. There can be beautiful stones for Good cut which are dinged for some reasons. Especially spreaded stones with depth lower than 58 are desirable for pendants as they appear large. However spready Good cut stones are much rarer as cutters these days aim to save weight while cutting.
 
GIA report

Measurements 7.09 - 7.14 x 4.23 mm
table 64%
culet - very small
Girdle thin to medium 3.0%
Carat 1.28
Color G
Clarity SI1
Cut Good
Polish Excellent
Symmetry Excellent
Flourescence None
I dont understand the diagram of proportions. I tried going to the link above to calculate.. I dont know.
 
Are you sure the table is 64%? That could be one reason it is only getting a good rating. We usually try to stick with tables
between 54-58%. There are some stones that are called 60/60 stones that are 60% table and 60% depth but I dont think anyone
would think 64% is good.

Edit ...here is a GIA cert, these are what the numbers mean.

table = 56
depth = 61.1
crown angle = 34
pavilion angle = 40.6


Did you find the stone on line? Can you give us a link to the stone?
 

Attachments

I actually called GIA and they told me if only the table was changed to 61% the cut grading would be very good. Also if they change only the pavillion angle to 41.3% it would change it to very good. It dont think its that bad. The word good is throwing it all off. I can get a smaller stone 1.17 in a triple Ex for $900 more though but you cant tell the difference in quality side by side except the 1.28 looks larger because its pancaked... wider top. What should I be paying for this 1.28 stone? anyone have an opinion on it?
 
Use the hca tool to see how it scores. Decent stones usually
Scope 2 or below.

Your values are
Table 64
Depth 59
Crown 32
Pavilion 42.2

https://www.pricescope.com/tools/hca

This stone may look ok under jeweler lights but it is not going to
Perform like a well cut stone would/should perform. All the little changes it would take to get to a well cut some would be a lot.

Here are the numbers we try to stay in when looking for a well cut some.
Table 54-58
Depth 60-62
Pavilion 40.6- 41 degrees
Crown 34-35 degrees

Can you request an aset image for your stone and post?

What kind of money are you talking about spending? We might be able to find you something nicer for around the same cost.
 
Go for the triple Ex. We would still like to see the numbers on that one.

64% table looks bigger....honestly all it does is put off a big amount of glare (not sparkle, glare). And, because it has a low crown you will
Probably see very little fire. Please don't buy this stone because it's a little bigger. It's just not going to perform like it should.
 
The smaller GIA stone was an H. triple Ex. 1.17 VS2 for $7,500 and the G we are discussing is $6,600. I think the dealer will go down a bit.
 
it actually looks very well proportioned. It is not ugly at all in real life.
 
joelcoqui|1442878358|3930364 said:
it actually looks very well proportioned. It is not ugly at all in real life.
Click to expand...
:wall: ..If that stone looks good to your eyes then you should go and look at some really well cut stones. As the table % get bigger the price gets cheaper + the cut quality will be lowered.
 
Thanks so much, I think im going to go with the triple Exc.
 
Wow, what horrible cut!
I'd reject any round that scores over 2.0 on the HCA.
That one scores 7.5. :knockout:

IIRC, 7.5 is the worst score I have ever seen.

screen_shot_2015-09-21_at_8.png

screen_shot_2015-09-21_at_0.png
 
joelcoqui|1442888273|3930401 said:
Thanks so much, I think im going to go with the triple Exc.
Click to expand...

Some GIA XXXs could still not have the best light performance.
Unfortunately GIA's top cut grade is not tight enough.
It allows high-profit steep-deep cuts to get an Excellent grade.

Be more picky to get better light performance:
Use the HCA.
Then get an Idealscope image on the rounds that score under 2.0 on the HCA.
https://www.pricescope.com/tools/ideal-scope
 
Can I post a pic for you guys and you decide the beauty of what Im getting? Remember Im not getting a stone for an investment, Im getting one for my future wife and we both have to love it no matter what the documents say. Thanks for all your input.
 
joelcoqui|1443009005|3930796 said:
Can I post a pic for you guys and you decide the beauty of what Im getting? Remember Im not getting a stone for an investment, Im getting one for my future wife and we both have to love it no matter what the documents say. Thanks for all your input.
Click to expand...

Sure, post pics...we would love to see them. But, remember, we want your stone to perform well in most lighting conditions, not
just one. Have you looked at this stone in various lighting conditions to see how it performs? Take it outside. Take it somewhere
out of jewelers lighting. Go somewhere and look at really well cut stones (AGS000 stones) and see if yours is performing like the
AGS stones. I would hate for you/your GF to decide at some point that its not doing what diamonds should do and become unhappy
with it. Its a lot of money.
 
Those kind of stones are probably best for a Men's ring! Large spread and much less amount of light return.
 
Please do post a pic or multiple pics. Perhaps you can even post pics of the triple EX that you're also looking at. Given the specs of the diamond I find it hard to believe it performs well. Could just be jewelry store lighting or perhaps it has some signature look that you find appealing. If you could post a pic of it and perhaps the other diamond or another that you don't really like then we might be able to determine why you like it and possibly recommend something better.
 
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