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John NC

Round Stone- Final Step, Best Compromise? Table, Depth, Clarity And Color Compromise, Iga Vs. Egl

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Barry- I agree with the sentiment of what you're saying. Many times a fluorescent diamond can be very pretty- specifically due to the fluorescence.

But if you're talking about a time when such stones commanded a premium, remember that D IF 1.00 carat diamonds used to cost about $4000. Consumers could buy gorgeous E-F/VS 1carat stones for $3000. In 1980 , for example, GIA reports were far less common.

Today the market is just different.

Every little comment on the report causes someone to question.

If it's online, some armchair expert is going to knock a stone because one of the upper pavilion facets is .00005 degrees off.

When we're talking about high dollar colorless IF-VS diamonds, fluorescence reduces the price by as much as 15%

In stones of G-H color it's less of a consideration- stones of I-J color fluorescence has little effect on price- even today.

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David;

 

We don't disagree. Today's market is different and based on the Cert first and then we look at the diamond.

 

Pricing for SB diamonds are what they are and there is no legit reason for it. Pricing was saner before the GIA paper trading and that includes the high color-clarity SB diamonds in the 70's early 80's.

 

Do you remember the benefits of laser drilling? Enhances the face up beauty of the stone without affecting its structural integrity but today you can't give a laser drilled diamond away.

 

Crazy but true. Where is Mr. Ripley?

Edited by barry

Barry
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David;

 

I did not twist your words at all. I quoted you accurately and directly and your assertion to the PO does not jibe with the results of the GIA study.

 

If you are going to dispense advice do so with accuracy.

 

Barry, you quoted me partially and in so doing you twisted the meaning of my words. I said that very strong fluorescence may OR MAY NOT be a problem. CHANCES ARE IT WON'T. Please tell me exactly where you disagree with these whole statments, not with selected words.

 

The GIA study says:

 

"Tradespeople further observed that some gem diamonds with a hazy appearance also fluoresced strong blue to UV radiation."

"The concerns about fluorescence can be attributed to a number of factors. These include notions that: [...] The hazy appearance seen in some strongly fluorescent diamonds must exist in more weakly fluorescent diamonds as well." (my emphasis)

"Diamonds with extremely strong blue fluorescence and a distinctive oily or hazy appearance, often referred to as “overblues,†are also a concern to the industry."

 

What makes you so certain that the diamond John is considering is not an overblue? Have you seen it? Have you spoken to someone who has? If so, fine, but disclose it. Otherwise, keep your advice about advice to heart.


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

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Why is it ‘rightful’ that inclulsions that have no affect on the visible appearance of a diamond but that are visible to a trained eye under 10x have a substantial affect on the price while inclulsions that require the experts to use 100x to find do not? There are, after all, optic physicists who would consider our definition of flawlessness to be utterly ridiculous. The fact that this difference has no affect on beauty is beside the point, rather like the fluorescence question, the weight question or, as another example, the country of origin question. All of these things affect the price because people consider them to be important and they vote with their money. Your example of laser drilling is another good one. This went from a neutral thing to a bad one with the stroke of a pen by some anonymous bureaucrat at the FTC. It may very well change back some day. The stones didn’t change but the market did.

 

Neil

Edited by denverappraiser

Neil Beaty

GG(GIA) ICGA(AGS) NAJA

 

There's never a crowd when you go that extra mile.

Professional Appraisals in Denver

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David;

 

You're correct, I have not seen this diamond but over the years I have seen over SB's and SB's and rarely are they a problem. Hence GIA using the word "notion".

 

In this thread where John is constantly asking us to opine and surmise "numbers" sight unseen, I was remiss in not suggesting an easy and obvious solution" Call the Vendor directly and ask if this over SB is a problem.


Barry
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Neil;

 

I believe it is "rightful" because clarity is a quantitative and qualitative measurement; even if not visible to the naked eye. VVS are rarer than VS's and SI's.

 

Both fluorescence and laser drilling each got bad raps because of one singular incident.


Barry
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Fluorescence is a quantitative and qualitative measurement as well. The question is not whether it can be measured or whether it affects the prices, we agree on that, it's whether it should affect the price. I guess we have to agree to disagree on this one. I see this as more of a psychology question than one of gemology or even history and there is no 'right' answer.

 

Neil

Edited by denverappraiser

Neil Beaty

GG(GIA) ICGA(AGS) NAJA

 

There's never a crowd when you go that extra mile.

Professional Appraisals in Denver

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HI FOLKS!

Wow Neil I'm a big fan, read many of your comments on several discussion boards. Lauren you too! Of course David and Barry your continued help is greatly appreciated-- I'm closeto pulling out the wallet!

 

David I sent that AGS 0, F, 2.04 $9,750 round (SI2/ Strong Blue the only apparent knocks) just to try to illustrate that it does appear the fluorescent diamonds trade at a discount, right or wrong. In fact in my searches it seems that the first (lowest priced) GIA diamonds that appear either have a 'good or very good' cut or they fluoresce in varying degrees (again right or wrong). Several people spell it differently- I've seen fluorescence, flourescence and florescence so forgive me if I get it wrong.

 

I'm trying to get away from focusing on table and depth percentages, as I told David yesterday I saw some diamonds with smaller tables and they seemed more lively (to me)- I liked the way the upper faces got into the game more quickly than a broad table would permit. Before for some reason I thought a bigger table was key paired with a 62% depth. David you sent me two 56 table, 61 depth diamonds the other day to review, is that a combo you are a fan of? Again trying to stay away from focusing on #'s, but they are a start.

 

I had nightmares last night about steep/ deep diamonds, as it seems that Cathy (another very popular post as she's looking for a similar round) and I seem to be finding diamonds with this potential shortcoming. Seems like the pavillion, pavillion angle, and excellent symetry are the engine room of light return (in my dangerously un-diamond-educated mind), and if the combo is wrong light leakage and overpaying for dead weight are the caveats. David brought this phenomenon to my attention, although my techincal description here I'm sure leaves a lot to be desired.

 

Lorelei posted on pricescope a tuturial on percentages and angles. Very interesting post, if anyone wants to read it in it's entirety here it is: http://www.pricescope.com/idealbb/view.asp?topicID=108304

The part that caught my eye and opened my eyes is this:

Lorelei """Here are some numbers you can use as a guide to find a well cut round diamond. Also to narrow the field you can look at AGS-0 cut grade and GIA Excellent, with these though use the HCA in the first instance to check those that score under 2, these are the ones worth further evaluation with ASET images etc.

 

depth - 60 - 62% - although my personal preference is to allow up to 62.4%

table - 54- 57%

crown angle - 34- 35 degrees

pavilion angle - 40.6- 41 degrees

girdle - avoid extremes, look for thin to slightly thick, thin to medium etc

polish and symmetry - very good and above

 

 

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!

 

 

 

From expert John Pollard.

As the above implies, configurations depend on each other. A little give here can still work with a little take there.

 

 

With that said, here's a "Cliff's Notes" for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

 

 

GIA "EX" in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35)."""

 

Ok back to me (John)- Looking at a page on goodoldgold talking about how to determine an ideal cut after Jan. 06 this is what I saw:

http://goodoldgold.com/4Cs/Cut/IdealCutDiamonds/

Seems that Tolkowsky recommended a crown angle of 34.5 and a pavillion angle of 40.75. AGS show's 33.7- 35.8 crown angle and 40.5 to 41.5 pavilliion angle, but then it says in text that the pavillion angle can range from 40.2 to 41.2, which is ever so slightly off from the graph.

Seems AGS-0 has it over GIA Excellent, especially if you aren't up to snuff on processing the percentages and angles.

Looking at Lorelei's post a 34 crown angle should pair with a 41 pavillion angle, and a 35 crown angle should pair with a 40.6 pavillion angle... roughly, with varying inverse relationship combos available within the acceptable ranges for the highest possible light return? Mercy this is tough!

Any comments would be a huge help- Thanks, John


John, Southeast NC

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Neil;

 

I believe we agree :rolleyes:

 

The links you posted are good general guidelines but more "numbers" crunching which really doesn't solve your buying decision. Two diamonds with the same numbers can look different. Ditto for Ideal AGS graded diamonds.

 

Get out there and l@@k at the diamonds.


Barry
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Thanks Barry- it is amazing that 2 similarly graded diamonds can look so different. The one's that have the fire and 'light' really stand out and grab you.

 

Neil and Lauren FYI I've been looking at 2+ carat round SI-1/2, G,H,I color going for Excellent cut GIA, with exc symetry and exc or very good polish- and trying to keep it under about $13K. AGS-0/ Ideal with all else being the same. Eye clean SI.

J color is an option too but I'd like to stay with GHI if I can... then the devil in the details... crown and pavillion angles and crown and depth percentages. If either of you have a quick cheat sheet to make sure I'm on the right track I'd appreciate it.

 

I know you all have lives outside of helping complete strangers across the globe, and I surely appreciate your time! Regards, John


John, Southeast NC

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John;

 

I'm a bit puzzled as to why you keep coming back to the "numbers" time and again in spite of the consistent advice offered here for you to get out there and correlate these "numbers" to your visual inspection. You already have the quick cheat sheet with the "numbers".

 

Time to travel and l@@k.


Barry
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I'm with Barry. You need to be looking more at diamonds and less at lab documents. What you're hoping for, specifically a way to milk more information about the quality of the stone from the data printed on the report is simply not there. Wishing it was does not make it so.

 

Neil


Neil Beaty

GG(GIA) ICGA(AGS) NAJA

 

There's never a crowd when you go that extra mile.

Professional Appraisals in Denver

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Yes the reason I posted that info from Lauralea is to verify that those pavillion and crown angles were good numbers to use as rough guidelines. I don't want a shallow or deep cut diamond. That info (ca/pa) is available on the GIA docs so I figured I'd use my reference points to try to do just that, make sure that along with the excellent cut the crown and pavillion angles are within preferred specs.

Time to look at some stones (other than all the mall and B&M/ in house graded stones around here). Thanks, John

ps- what would help is if ALL the grading labs took photos of their diamonds under the H & A gadget (to show symetry or lack thereof, and provided Sarin and Idealscope images... plus the other helpful data, and if all "G" diamonds were truly "G"- for instance an EGL G might equal a GIA I or even J. Equal the playing field some. Thanks again!

Edited by John NC

John, Southeast NC

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John, my name is David.

 

I have to tell you it's amazing.

This is a very common occurrence.

Someone comes on to this, or another forum to ask a question.

"What crown angles, Pavilion depth, table and depth should I look for.

EVERY time, the informed answer is: You can't tell if you're going to love a diamond, or if it's is well made based solely on the numbers from the GIA or AGS report.

 

Otherwise seemingly intelligent folks than ask...Ok, but if I was going to look for numbers, what should they be....

Where's the pulling hair out of head smiley when you need it....

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David;

 

This is why I have asked Hermann ( the site owner and Admin) to set up an FAQ section here so that members can source their question and already given answers.


Barry
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Hi David, I thought your name was Lauren based on your log in name I guess... regardless I have read some of your responses and found them informative.

I'm sure it's frustrating for the pros for a guy like me trying to learn, never having bought any high quality diamonds to come in and try to make an informed decision- almost like throwing a dart at a dartboard of 40 GIA Ex, AGS-0 diamonds... you just want to get all the diamonds that don't perform like you want for the $$$ off the board before the dart hits. And the only way to do that is to narrow it down based on numbers. Unless you can walk into a showroom of 20 high quality GIA/ AGS 2+ carat diamonds, which there are none around here- just lots of mall stores and B & M stores with mainly in house graded stones and high priced at that. And if they have GIA/ AGS stones they're $10K per carat H/I/J 'pretty good' overall. I know you can easily spend $20K plus on a 2 carat with top qualities overall... but again I'm looking for the best compromise for me.

I learn something new every day, looking at my top 10 from last week for instance I've rid myself of a few based on very thick girdles, high crown percentages, odd crown and pavillion angles, steep/ deep for instance to use a term the other David wrote, and a couple other parameters.

Sure a diamond with a 59% table and 60% depth along with out of the norm crown and pavillion angles, small culet, strong fluorescence, thick girdle, SI-2 with a visible inclusion might be pretty good looking, but I'd rather stick with the classic proportions that are proven to perform... maybe get just that much more sparkle and pizazz that makes you say "WHOA!" instead of "whoa... ahem... Oh, I mean, it's beautiful... so how about them Yankees?"

Thanks again- John


John, Southeast NC

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Thanks John.

The advice is simple. Use your intuition to pick a dealer.

While it's simply NOT possible to learn the intricacies of diamonds in a short period of time, you already have all the tools you need to pick a good dealer. You know human nature.

 

Personally, I prefer a stone with a slightly larger table, such as 60%.

But if you want to believe everything you read, and based on your comment about 59% tables, apparently you do, a stone with a 60% table has something inherently "wrong" with it.

Nothing could be further from the truth, but if a person wants to try to become a diamond expert by reading the internet, that's what you get..

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David;

 

You're correct, I have not seen this diamond but over the years I have seen over SB's and SB's and rarely are they a problem. Hence GIA using the word "notion".

 

In this thread where John is constantly asking us to opine and surmise "numbers" sight unseen, I was remiss in not suggesting an easy and obvious solution" Call the Vendor directly and ask if this over SB is a problem.

 

Apologies for giving you some short shrift. Olive branch and handshake? :D


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

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John, the reason why I suggested those two diamonds from Whiteflash is because WF are very consistent at choosing excellently cut diamonds, and those two were the closest I could come up to your desired specs. The consistency shows up in the reported measurements, but it's not a question of 56/61 good all else bad, although I'm sure if you looked at either of those two you would be going "WHOA! Where's my sunglasses?" although they don't quite "fit" with your notional constraints.

 

The guidelines/tips you got from here (more begrudgingly, because "as a board" we are more skeptical of absolute, fixed claims to perfection) and from Lorelei and John Pollard (far more easily, for the opposite reason) are all perfectly reasonable, but there comes a point where you need to start looking at physical stones rather than numbers.

 

If you can't do that because of your location/credit card limit/willingness to take risk and pay shipping charges, then you need to choose someone who can do some of the winnowing for you and present you with good options - ideally incorporating as much data, photos and "technical" detail as you feel comfortable with.

 

Quite a few of the posters here have an excellent reputation, access to broad stocks and are very committed to giving consumers good value for money. Why don't you call a few of these people, have a chat with them explaining what you are looking for (do call Barry - he fits all the criteria above plus he knows all the story!) and see what they can come up with that fits your criteria plus maybe a couple of things "out of left field" that may just stretch your perceptions/preconceptions a bit? Digital pictures are cheap, and some dealers may even make movies for you to see the diamond "live" in different lighting environments.


Davide - Specialised Consumer Information and Assistance,
Diamonds by Lauren (http://www.diamondsbylauren.com)
davide@diamondsbylauren.com

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Hi Guys, Yes time to break out the credit card and start looking at stones. David (diamondsbylauren)- I wasn't trying to say that I don't like diamonds with a 59/60 table... I was just trying to list an odd combination overall, and make the point that it might be beautiful in it's own right. No offense meant of course.

My obsession with trying to get a grip on the numbers was to get educated to some degree and try to avoid a diamond that might not have a great light show.

Diamonds are hard as heck to buy! Such an emotional purchase, and then your analytical side kicks in while trying to get the details right, then your budget side kicks in, and quickly gets kicked out... When this whole deal is done I'm going to sleep for 2 days- went to sleep last night thinking about diamonds, woke up thinking about them.

Thanks- John


John, Southeast NC

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