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Best Way To Evaluate Diamond's Cut?


pfq1982
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What's most important and how does one pinpoint the best cut (at least on paper?)? Many stones I see in stores advertise color/clarity/weight with very little regard to cut or some of the details specifics many posters put on (tables, depths, angles, polish, symmetry, etc.)

 

Also an unrelated question: Does putting more facets on a stone (Liek a Leo Diamond) increase its potential for brilliance, assuming its cut just as well as a usual 57 faceted stone?

 

All questions related to colorless rounds.

 

Thanks a ton!!

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If all you’ve got is the paper and you’re considering calling in a round brilliant cut stone for further examination, the thing to look for is the GIA or AGS assigned cut grade. This appears on every GIA report on a modern round brilliant cut issued since 2006 and on AGS reports issued after 1996 (the founding date of the lab).

 

If you’re looking at a non-round or non-standard round or the report predates tha above, it won’t contain a cut grade at all and you simply can’t make any sort of reasonable assessment about the quality of the cutting using the information provided.

 

No, the number of facets does not affect the total light return. It's the angles of the facets and the relationship between those angles that does this. Extra (or fewer) facets changes the size and shape of the sparkles which consequently changes the 'look' of the stone, and some folks like the affect, but it's not correct to say that it's 'better'. It's different. Only you can decide if it's an improvement.

 

Neil

Edited by denverappraiser
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pfg- I'm curious to know if you've looked at modern round diamonds in person- and compared to the Leo cut.

I'd really be interested in your opinion.

Another aspect which I'm always interested in what "normal" people- as opposed to those not involved in the trade- see as beautiful, when comparing two well cut round brilliant diamonds.

 

Since we're talking about round brilliant, let's also assume the only diamonds we can consider well cut are those with a GIA ( or AGS) report graded EX, or VG cut grade ( or triple 0 for AGS)

Have you ever looked at a few stones in comparison?

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First of all I would make sure the stone I'm getting ready to purchase has a GIA or AGS lab report. I don't believe they offer that type of report for the Leo.

Secondly look for an ideal cut if AGS or Excellent cut grade from GIA.

 

If you want to sort out the best of the best, then get some light performance analysis done on the stone as well such as a brilliancescope or Isee2.

 

 

www.gemex.com

www.isee2.com

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To clarify a little more, many dealers that don't handle the top makes won't be a fan of the machines that tell the light performance as their stones won't do well if only mediocre cut grades. They would rather just tell you the stone is a "nice stone" and hope that you will listen to them with no concrete proof.

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The best way is to "see" the diamond or have good information and physical evalution to back it up.

 

The whole point of having a top cut in a round brilliant is to have top light return I would think. So just measuring external dimensions doesn`t give the total information or proof that one diamond is any brighter than another. Even within in the two major labs grading cut now (GIA & AGS) there will be differences in appearance with the same cut grade.

 

Here is an example of a recent diamond that was graded by AGS as Ideal in all aspects of cut and performance.

 

Here is the Brilliancescope reading

 

http://www.gemex.com/livereport/partnerlin...id=db92vs1h2494Live Report

 

And Here is the ISEE2 reading.post-114043-1231895488_thumb.jpg

 

I don`t think all three could be wrong that this is a diamond with top light return.

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To clarify a little more, many dealers that don't handle the top makes won't be a fan of the machines that tell the light performance as their stones won't do well if only mediocre cut grades. They would rather just tell you the stone is a "nice stone" and hope that you will listen to them with no concrete proof.

 

Interesting Jan- that would mean that Tiffany's, Cartier, Harry Winston, Graff- all of the guys are selling badly cut diamonds since they don't use these machines?

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The best way is to "see" the diamond or have good information and physical evalution to back it up.

 

The whole point of having a top cut in a round brilliant is to have top light return I would think. So just measuring external dimensions doesn`t give the total information or proof that one diamond is any brighter than another. Even within in the two major labs grading cut now (GIA & AGS) there will be differences in appearance with the same cut grade.

 

Here is an example of a recent diamond that was graded by AGS as Ideal in all aspects of cut and performance.

 

Here is the Brilliancescope reading

 

http://www.gemex.com/livereport/partnerlin...id=db92vs1h2494Live Report

 

And Here is the ISEE2 reading.post-114043-1231895488_thumb.jpg

 

I don`t think all three could be wrong that this is a diamond with top light return.

 

 

Brad- have you seen a lot of AGS Triple Zero ( Ideal Cut Grade) diamonds that were badly cut?

 

The machines are simply not accepted by many of the best dealers in the world.

Consumers looking for a really well cut round diamond need to go for a diamond with the top cut grade from GIA (Ex) or AGSL Triple Zero.)

 

The machine will give different results on the same diamond if you place it on the tray differently- there's so many reasons the machine s shunned by most in the trade.

I'm sure that you know how to use the machines Brad - and l'll bet you take good care of people that choose you as a supplier.

But it does not change the fact that the companies pushing these systems do not provide useful information for consumers.

Nor the fact that most of the world's top diamond dealers see no value in them either.

Edited by diamondsbylauren
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No doubt, The absolute best way to evaluate a diamond and to decide whether or not to buy it, is to actually see it in person.

 

The salient feature to keep in mind here is that it's beneficial to compare apples to apples, not apples to oranges. Tiffany's, Cartier, Harry Winston, and Graff sell beautiful diamonds but they sell them from inside their B&M store locations and not through their websites. The websites are designed to showcase their rings and settings.

 

So what about those people who prefer to shop their diamonds on the Internet. How can they "see" these diamonds? We believe that the current technologies which provide optical performance information about a diamonds cut and light refraction serve a very useful purpose and help Internet shoppers in this regard.

 

We use Brilliancescope, Idealscope, ASET scope, the Holloway Cut Advisor (HCA) and photographs to evaluate not only "Ideal" round diamonds for our customers but also 60-60's Table-Depth round diamonds as well as Fancy shapes. These tools individually have their limitations, but all the results taken together do accurately convey the essence of the diamond and help the consumer make a decision from his computer screen.

 

The fact is that a skilled diamond cutter crafting a round diamond can achieve beauty outside of current "Ideal" proportions of 54-57% table and 60.6- 62.3 total depth. This beauty is also captured by these tools. Ditto for fancy shapes for which there is no definition of "Ideal".

 

These tools help us to help Internet shoppers.

Edited by barry
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I`ve seen many AGS ideal cuts that had medicore light return. I wouldn`t say they were considered poorly cut, but less than great on the light return. They are certainly not all the same in that area.

 

We get many customers that do want more than a lab report. They usually ask us for a diamond that has exceptional brilliance, fire, and sparkle. This is something we have a lot of experience with and have a very good system and track record at selecting diamonds with top results.

 

I think the information is useful to consumers that want more evidence of what a diamond is claiming to be. More than a piece of paper that says Ideal or Excellent. Especially with buyers on the internet who are mostly relying on numbers and paper to predict the look of a diamond they haven`t seen.

 

With many internet sites that don`t even see the diamonds they sell themselves, I find the added effort and expense we incur to provide our customers with added light performance information a plus.

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Excellent points Barry, and Brad.

I overlooked the value to the extent that there are many people that feel comfortable buying based on measurements and statistics.

 

I have no doubt that both of you- and many others- use the results of these tools to the best of their intended uses- and shoppers, no doubt, get some perceived benefit.

But for me, the bottom line is still going to be your ( or any) company's excellent reputation- and your ability to judge the diamond you are shipping.

 

Of course this means you must test any diamond you are buying for stock.

We don't advertise a lot of round diamonds- which also colors my viewpoint.

If we did, I would likely need to use the results of these machines in buying to determine what would look good on the computer screen.

 

Regardless, I still stand by my statement regarding the best way to evaluate a diamond's cut- physical inspection and evaluation. With the eye being the final arbiter.

Edited by diamondsbylauren
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Thanks all for the replies.

 

Lauren; I have seen a number of brilliant rounds in person in the specs you described. It's very easy to perceive difference in color, but it's a little difficult to tell the difference in fire/spark/brilliance between stones. And from the stones I've seen, I haven't been able to perceive difference in clarity, most else being equal.

 

I haven't seen the Leo, but I've seen "Hearts on Fire" compared to Exc/VG GIA-rated cut stones of similar color clarity. To my untrained eye, I thought the other stones were similar in flat light but the Hearts on Fire showed more sparkles under direct light. Any suggestions for how to compare difference in brilliance when I'm seeing two or more stones in person? All I do is tilt them together, let the eyes zone out, and try to see which one sparkles more if that makes any sense. Any technique? To me, I don't see a difference, but it bothers me to know that intrinsically one must be better than the other and I'm sure a trained eye can tell. Subjecting the stones to a battery of light performance tests sounds pretty appealing to me. But then again I'm a mathematical type. Frankly every other high-dollar purchase I can think of has some sort of performance benchmarking (computers, cars, appliances) and I'm surprised this industry seems out of touch. Is there anyway for me to "light-test" stones I see at dealers?

 

Also, some thoughts from shopping in NYC... It's remarkable how the sales people pressure / expect you to make a decision to buy a stone after 1 or 2 trips and after only seeing 3-5 stones in person. When I'm buying the most expensive non-financial product in my life so far (by a long shot), I want to cross the T's and dot I's. Sometimes they try to tell me sob stories about "$300 to ship from our overseas store for you to look at it". If I'm going to spend $8-15k + setting, I don't care about YOUR sob story. I'm the one inevitably getting screwed!

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Adding one more thing -- in my "blind" tests of VG vs. EXC GIA-rate cut rounds, I have NOT been able to tell a difference in brilliance. (sample size not statistically significant!)

 

I want to see what that fellow from Colorado that comments a lot calls a "fireball". Something that's in the 90 - 99% percentile for brilliance. From limited stones I've seen, I haven't seen any atomic fireballs that outshine the rest, but my eye is untrained... I can't even tell the difference between VG and EXC cuts all else equal!

 

 

Thanks all for the replies.

 

Lauren; I have seen a number of brilliant rounds in person in the specs you described. It's very easy to perceive difference in color, but it's a little difficult to tell the difference in fire/spark/brilliance between stones. And from the stones I've seen, I haven't been able to perceive difference in clarity, most else being equal.

 

I haven't seen the Leo, but I've seen "Hearts on Fire" compared to Exc/VG GIA-rated cut stones of similar color clarity. To my untrained eye, I thought the other stones were similar in flat light but the Hearts on Fire showed more sparkles under direct light. Any suggestions for how to compare difference in brilliance when I'm seeing two or more stones in person? All I do is tilt them together, let the eyes zone out, and try to see which one sparkles more if that makes any sense. Any technique? To me, I don't see a difference, but it bothers me to know that intrinsically one must be better than the other and I'm sure a trained eye can tell. Subjecting the stones to a battery of light performance tests sounds pretty appealing to me. But then again I'm a mathematical type. Frankly every other high-dollar purchase I can think of has some sort of performance benchmarking (computers, cars, appliances) and I'm surprised this industry seems out of touch. Is there anyway for me to "light-test" stones I see at dealers?

 

Also, some thoughts from shopping in NYC... It's remarkable how the sales people pressure / expect you to make a decision to buy a stone after 1 or 2 trips and after only seeing 3-5 stones in person. When I'm buying the most expensive non-financial product in my life so far (by a long shot), I want to cross the T's and dot I's. Sometimes they try to tell me sob stories about "$300 to ship from our overseas store for you to look at it". If I'm going to spend $8-15k + setting, I don't care about YOUR sob story. I'm the one inevitably getting screwed!

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What’s the performance benchmark for clothing that makes one suit cost $99 and another $1000? How about wine? What do you measure that justifies why one cost 10x more than another? For that matter, cars don’t all use the same benchmarking and it would be easy to design a set of tests where a Hyundai would outperform a Lamborghini. If your target is maximum faceup light return when viewed from the central axis with direct overhead light, I’ll agree with Bradley that the Gemex tool does a good job of demonstrating that. Frankly, that does seem to be what you're asking about and the Gemex website has links to their dealer network. Check and see if there's one nearby. If you’re objective it to measure beauty it’s a considerably more difficult question. The HoF brand does pretty well at balancing all of the variables and they are widely distributed. That gives you the opportunity to actually look at stones in person and compare what the differences are. Most high quality dealers will have some stones that they sell at a premium for this purpose and will be happy to show them to you. Look at them in a variety of different lighting and see what your taste is like. This is what the sales people are for. If you don’t care for, or can’t see, the difference, don’t pay a premium for it. It’s not correct to say that these stones are ‘better’ but they are popular and they are more expensive.

 

Neil

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I understand why you feel the way you do pfg- and there are certainly places that will cater to your desire to offer numerical measurements of brilliance.

However I still feel that it's a misguided way to buy a diamond.

Neils example of how a car manufacturer can make a Hyundai seem more powerful than a Ferrari is a very good one.

Clearly there is great debate between dealers about this subject.

 

I believe that it's not the industry trying to be deceptive- or failing to keep up with technology- rather my feeling is that trying to create a system to rate what the eye finds beautiful is misguided.

Edited by diamondsbylauren
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