Larger table than depth?

[harvey]

Hello all. I am brand new to this diamond stuff. I recently picked out a diamond 1.23 carat, G-color, SI2(one feather and twoclear crystals, all off the table) 60%table and 58.8% depth, Ex polish/symmetry, slight -med flourscence, GIA cert. The diamond looks great, but I have only really looked at ~10 diamonds. After researching cut in great detail today I am kinda worried about the table and depth percentages. The diamond does not score well with cut on the AGS scale b/c its not 59% depth, however it does score well on the AGA scale. I do not have the pavillion and crown angles and do not think that I can get them. Is it bad that the table and depth are at opposite end of thier respective ranges when grading out for cut? The stone is for an engagement ring and it looks bigger than a 1.23 carat, which is expected and I like that. Does anyone think I should go for something with a little better proportions. According to the "new" Gia study "some diamonds with larger tables exemplify more brilliance" yeah but with what depth proportions? I''m confused. Any input would be greatly appreciated. Thanks ahead of time.

 

[Magnum]

It's hard to comment on the cut of the diamond without crown and pavilion angles. Those in the 60/60 camp might say it looks pretty good, but personally, I would need more information to make that determination. Seeing it with your own eyes is definitely one of the most important tests, but make sure you've seen some diamonds with excellent cut that you can compare it to.

As far as the relationship between table and depth is concerned, if you hold the pavilion angle, crown angle, girdle, and culet constant, by increasing the table size, the depth is going to decrease. So it is not out of the ordinary to see a smaller depth with a larger table. In fact, i would expect it. Think of it this way. Take a diamond with a 40.7 pavilion angle, 34.5 degree crown angle, medium girdle and no culet and give it a 55% table. Now if you slice off part of the top of the diamond parallel to the table, you've just increased the table size (say made it 62%) and decreased the total depth. the pavilion and crown angles are the same, and so are the culet and girdle. You've just taken a slice off the top which decreases the crown height, and thus the overall depth percentage is decreased. It would probably help if I could post a diagram, but hopefully what I said makes sense.

As far as which is better (a little deeper diamond with a smaller table or a little shallower diamond with a larger table), that's probably a personal decision. Assuming both have the same angles, some prefer a smaller table because there's usually a little more dispersion (fire) in the crown, whereas others prefer a larger table because it makes the diamond look bigger for the same carat weight and is usually a little more brilliant.

 

[hoorray]

There is a recent thread that depates 60/60 depth/table stones, and the conclusion was that there are some beautiful ones, but what determines whether they are beauties or dogs are the crown and pavilion angles. It's no different with stones that have tables and depths in the ideal range. Thus, you really need to either get these angles, or use an idealscope to look at the light return, or take the stone to an independent appraiser you can give you this info. You simply don't have the full information to know.

Cut nut has also posted some info lately about shallow stones -- saying they might appear dark up close due to your head blocking light to the stone, so are sometimes are better for pendants of earrings.

Do some searches to find these threads so you don't have to rely on my paraphasing. And remember, at the end of the day, it's about what your eye likes, (in everyday lighting -- not just jewelery store speciality lights.)

 

[valeria101]

LINK

Honestly, the stone may or may not loose fire with a large table - at least in ideal cuts most of dispecrsion would come off the table anyway. It would not be practical for me to make a model of the stone manually, but the $20 of an Ideal Scope would help both to asess this stone in comparison with ALL others (see ref chart

) and to evaluate any other rounds with no stats you might be considering - if this stone does prove dissapointing and there is recourse.

I would not spend that much money on a diamond without having seen quite a few more than 10. No, I am not under preassure to provide e-rings or anything, so I have the opportunity to research these little overvalued assets to death

 

[harvey]

Thanks for the replys. I am getting it from a guy that I know well and that has a very good reputation. He said he does not have the pavillion and crown angles. Should I insist on them? He mentioned that if the crown and pavillion angles are off by too much that it is commented upon on the GIA cert, I think he said if they are greater than 35 and 41 respectively then a comment is made. Is this true? The price of the diamond is $5000(includes setting), I know I could maybe go a little cheaper on the net, but I like a local guy with service, trade in, buy back etc. Jus tout of curiosity which is the worse number on this diamond? Table or depth? How many of you would not buy this diamond because of those percentages? Anymore comments would be greatly appreciated.

 

[Rhino]

Hi Harvey,

I think it is *good* that you've found a local you are comfortable with. Since he is concerned about serving you properly, INSIST upon diamonds with excellent sets of proportions. If he doesn't have the technologies to determine this HE CAN GET DIAMONDS FROM FACTORIES THAT DO PROVIDE this basic information or have him locate an AGS "0" diamond for you with certain optimal sets of ideal proportions.

If you are really looking for deeper information regarding this diamond it is impossible to make any kind of educated assessment concerning it's light performance based on table/total depth info alone except for the fact that it will have a good spread. Stick with your jeweler and express your concerns. If he is truly interested in serving he will find what you are looking for.

 

[harvey]

Thanks Rhino. I agree that having a local guy can be valuable. He sells 50-75% to stores and 25% to individual buyers. He sat down with me for 1.5 hrs going through different diamonds and their GIA certs pointing out inclusions/color differences. Once we narrowed it down he went over each specific defect/inclusion and told me "if any of those bother you don't get it." I thought he was very straight up with me, and he doe not "need" to sell this diamond. I am just having second thoughts after reading all the info on cut specifications. I am wondering if I could get something "better" for the same price. I plan to just voice my concerns and go from there. Thanks for the input. Rhino do you know anything about crown and pavillion angle parameters for GIA cert like I mentioned previously?

 

[Rhino]

Hi Harvey,

Yes. GIA generally comments when crown angles are over 36 degrees (if memory serves me right) but insofar as I know they make no comments on pavilion angles. I've never seen comments from GIA on pavilion angles. Frankly ... while I greatly value the information on a GIA Report (what they do grade, they do so accurately), I can not and do not make a purchasing decision based on a GIA Report alone. If I were you and were going to get a GIA stone I would insist *at least* on getting some basic Sarin data. Of course the more detail the better. See how he responds to you when you request this data. And consider that this is (for alot of people), a once in a lifetime purchase. It's painful for me to part with even $500 much less the thousands it costs for a diamond. At least get the basic Sarin data and the people on the forum here, including myself can help you better with that info.

 

[harvey]

How hard is it to get a sarin run on a stone considering I am in a metropolitan city and my seller does not have the equipment hisself. How much does it cost? Is it an expense the buyer or seller should pay for? Could my seller just call up GIA and get the info? Any info appreciated.

 

[Rhino]

Unfortunately not that easy. GIA does not release the info. If you are in a metropolitan city hit the yellow pages and start calling appraisers. Let them know you don't necessarily need a full blown appraisal at this time (although you may want to do that too) but if they have a Sarin and if it would be possible if you could bring a diamond or 2 to have them check it out for you and give you a print of it. If they know they'll get your business on the full blown appraisal this will motivate them to help perhaps. I've heard of some appraisers doing this for approx. $15-$20 a pop (if memory serves me right).

 

[valeria101]

You ask if anyone would avoid the stone... you bet

Since I do not have it infront of me, in some way I get to form an impression on your stone as I wold about any diamond being presented online - and the expectations I can form based on my knowledge ( ok, this is just a hobby, so my opinion needs a big grain of salt, I'm counting on that

) and your description do not feel great. Admitedly, it is harder to trust a set of numbers presented online than it is to get enchanted by the sparkle of a diamond in person. But this is a good thing: it just means that there is allot more information going with "virtual" diamodns and it can compensate quite a bit for one's inability to actually handle all those diamodns for which "numbers" are available

I am not so sure about local service: jewelry is rather durable, hardly needs professional maintainance, and most online sellers also have trade-up policies and their own established stores, only not very close to my current address

It just so happens...

 

[harvey]

Thanks for all the opinions. I forgot to add that the stones diameter is 7.01mm. I imagine there is a way to tell if the stones percentages are "on par" with the given diameter in respect to expected percentages for a well cut stone? I was going to try Diamcalc but the download is not working.

 

[valeria101]

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On 5/16/2004 9:45:08 PM harvey wrote:



I imagine there is a way to tell if the stones percentages are 'on par' with the given diameter in respect to expected percentages for a well cut stone?

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yeah... a Sarin report!

You would not be able to use DiamCalc without more "numbers" available for the stone, I am affraid. I am not aware of a shareware version of DiamCalc, but you can always use the free CutAdvisor here.