Finally (almost) decided on E-ring!

[orymd]

I am going to see it in person tomorrow - It is being shipped from a different store location. After giving it much thought, and going back and forth between Tiffany and Cartier 1895 setting, i decided to go with the six prong classic setting from Tiffany with the largest diamond I could afford within my budget. It is a Tiffany solitare (Tiffany setting) 1.49 I VS2, and I was told that it is a triple ''excellent''. What does that mean? And, is there anything else that I should check out when seeing it in person tomorrow? I am very excited and if all goes well am hoping to get it resized to her tiny 3.5 finger size. I am planning to propose on our one-year anniversary, July 6th.

Thanks for everyone''s help!

 

[Megenoita]

You are getting a genuine Tiffany setting, or a Tiffany-style setting?

Triple excellent means that the diamond is graded by GIA (most likely) and GIA gave it its highest rating for Cut, Polish and Symmetry. Triple Ex stones typically command a premium in the market.

If I were you, you should check out its HCA score (Holloway Cut Advisor) because it can show you a red flag if the stone''s cut is off. In the HCA, you want an overall "Excellent" rating. Not all GIA Ex/Ex/Ex stones are cut to display the most brilliance, fire and scintillation, and the HCA can help reveal if the cut could be better. On the other hand, if you have a GIA xxx and the HCA is strong, coupled with your eye seeing that it is a knockout diamond, you can rest assured that you have a great stone.

M

 

[mrscushion]

How exciting, orymd!

Megenoita is right on, you should utilize the Cut Advisor tool if you can:

https://www.pricescope.com/cutadviser.asp

To do so, you will need data from the diamond''s GIA certificate, so ask to see that tomorrow.

Good luck!

 

[Lorelei]

Yes, triple Ex usually means a GIA graded diamond of excellent cut grade, polish and symmetry.

 

[orymd]

Yes, the ring is from a Tiffany store so they do not provide a GIA but their own certificate. Megenoita, should I still be looking for HCA score?

THANKS!

 

[Lorelei]

Date: 6/30/2009 11:57:13 AM
Author: orymd
Yes, the ring is from a Tiffany store so they do not provide a GIA but their own certificate. Megenoita, should I still be looking for HCA score?

THANKS!

You can use the HCA certainly, one thing you don''t need ex across the board with the HCA as it is usual for all but the more shallow depthed stones to get a VG for spread, this is fine.

 

[orymd]

Lorelei thanks for the reply... Do you mind giving me the ''diamonds for dummies'' translation of what you just posted? I didn''t quite get it....

 

[Lorelei]

Date: 6/30/2009 12:12:27 PM
Author: orymd
Lorelei thanks for the reply... Do you mind giving me the 'diamonds for dummies' translation of what you just posted? I didn't quite get it....

LOL! No of course not!

The cut advisor ( HCA) is used as an elimination tool, not for selection. The aim is to find stones which score below 2 in the first instance, these are the ones worth putting on a short list for further evaluation.

If you look at the results of a diamond which has been run through the HCA, you will see it grades light return, fire, brilliance, scintillation and spread. Now these are only predictions as the cut advisor cannot physically see the diamond. With the grade for spread, where megenoita said look for all excellent results, it is only the more shallow depthed diamonds which get excellent for spread, so in other words you don't need excellent across the board.

Hopefully this link will post so you can see what I am referring to

https://www.pricescope.com/cutadviser.asp open the link and click go, that will bring the results up that I am describing.

 

[bootsiekin]

The dimensions you need for the HCA will be on the Tiffany certificate. Maybe you can ask them to get a copy of it? I know that they didn''t give it to DH when he bought the ring - they mailed it to him a few weeks later. It will show an image of the diamond and have all the dimensions labeled. (I actually pulled mine out the other day after learning about HCA - my stone scored a 1!)

 

[FB.]

Lorelei

The cut estimator that you have linked above seems to give rather different opinions on cut grade of rounds, compared to the GIA cut estimator.
With the same set of specifications, I can turn a GIA-graded "Excellent" into merely a "good" stone. Being new around here, I'm not looking to stir up trouble, but I'm a bit puzzled. Is it just that the GIA takes into account several more variables that - when combined - can have quite an effect?

Details of the diamond in question:

Table: 56%
Crown angle: 35.5'
Pavilion angle: 41.2'
Star: 55%
Lower half: 75%
Girdle min: med
Girdle max: slightly thick
Culet: none
Polish: ex
Symmetry: ex
Total depth: 62.8%

GIA estimated cut grade: Excellent.
Even if I drop the polish and symmetry to v.gd, it still comes back from the GIA calculator as Excellent cut.


........


HCA result:

Light Return: Good
Fire: Good
Scintillation: Good
Spread or diameter for weight: Very Good
Total Visual Performance: 4.4 - Good - Only if price is your main criterion

If I enter % instead of degrees on the angles for crown/pavilion, HCA result comes out as:

Light Return: Very Good
Fire: Very Good
Scintillation: Very Good
Spread or diameter for weight: Very Good
Total Visual Performance: 3 - Very Good - Worth buying if the price is right


..............................


For what it's worth, in real life, the stone listed above is a very nice diamond - at least, compared to others that I've seen.

 

[BCEagle03]

Does a store like Tiffany''s purchase stones based on their light performance?

One of the stores we are working with to buy a diamond says that they purchase stones first and foremost based on performance. The salesperson compared his store to Tiffany''s in that respect and said that only a few stores actually operate this way.

This partly came up in the context of having the stone insured. I was worried that if I bought a stone that was beautiful but only had VG/VG/VG that if I lost it, it wold be replaced with a mediocre VG/VG/VG stone. When we find insurance I will only go with an insurer who I know would replace the stone from the same store so that they will ensure proper performance.

 

[jet2ks]

Date: 6/30/2009 1:15:30 PM
Author: FB.

The cut estimator that you have linked above seems to give rather different opinions on cut grade of rounds, compared to the GIA cut estimator.
With the same set of specifications, I can turn a GIA-graded 'Excellent' into merely a 'good' stone. Being new around here, I'm not looking to stir up trouble, but I'm a bit puzzled. Is it just that the GIA takes into account several more variables that - when combined - can have quite an effect?

GIA Excellent cut grade has a pretty broad range and includes some combinations that may not perform well. The diamond you have listed is an example. The crown and pavillion angles put it into steep/deep range, which means the angles are not really a good match and the diamond may show some light leakage. This stone would not receive AGS's top grade for cut, as their ideal range is tighter than GIA Ex, and they are the only lab that currently grades performance--GIA rates cut purely on the numbers, polish and symmetry. Just FYI, angles are more accurate than percentages on the HCA.

The question becomes how much that leakage will show in the actual performance. IS and ASET images are useful for evaluating that aspect. Make sure when you evaluate a diamond in person to get it away from the bright showcase lights. Those lights are specifically designed to make all diamonds look good, even those not well cut. See if you can take the stone over near a window in order to evaluate in more natural lighting conditions. If you can take a look in a low lighting environment, that is where a truly great performing stone will outshine a pretty good one. One of the merchants who posts on PS has mentioned that she has customers compare stones under a table to show this.

 

[Lorelei]

Date: 6/30/2009 1:35:44 PM
Author: jet2ks

Date: 6/30/2009 1:15:30 PM
Author: FB.

The cut estimator that you have linked above seems to give rather different opinions on cut grade of rounds, compared to the GIA cut estimator.
With the same set of specifications, I can turn a GIA-graded 'Excellent' into merely a 'good' stone. Being new around here, I'm not looking to stir up trouble, but I'm a bit puzzled. Is it just that the GIA takes into account several more variables that - when combined - can have quite an effect?

GIA Excellent cut grade has a pretty broad range and includes some combinations that may not perform well. The diamond you have listed is an example. The crown and pavillion angles put it into steep/deep range, which means the angles are not really a good match and the diamond may show some light leakage. This stone would not receive AGS's top grade for cut, as their ideal range is tighter than GIA Ex, and they are the only lab that currently grades performance--GIA rates cut purely on the numbers, polish and symmetry. Just FYI, angles are more accurate than percentages on the HCA.

The question becomes how much that leakage will show in the actual performance. IS and ASET images are useful for evaluating that aspect. Make sure when you evaluate a diamond in person to get it away from the bright showcase lights. Those lights are specifically designed to make all diamonds look good, even those not well cut. See if you can take the stone over near a window in order to evaluate in more natural lighting conditions. If you can take a look in a low lighting environment, that is where a truly great performing stone will outshine a pretty good one. One of the merchants who posts on PS has mentioned that she has customers compare stones under a table to show this.

FB, I understand and please ask if there is anything you want to know or are not sure of! Jet has explained it well, GIA Excellent's parameters are pretty wide and allow for what we call steep deeps to get the Excellent grade, such as the diamond you posted. Basically what this means is as Jet explained, the crown and pavilion angles are too steep and deep to work well together, light leakage is often the result. This is literally light escaping from the diamond where it should be hitting you in the eye as sparkle!

Also as I explained above, the HCA is used really as an elimination tool, not for selection. The aim is to discover which diamonds score below 2, then these are the ones worth further evaluation, this is done with ASET and or Idealscope images plus trusted vendor/ appraiser advice.

 

[FB.]

jet2ks

But which of the three outputs should be trusted?

GIA - Excellent.
HCA using degrees - Good.
HCA using percentages - Very Good.


I would have thought that the greater number of inputs that go into the GIA calculator would give a more accurate result - especially since the HCA can''t seem to grade the same stone consistently, depending on degrees or percentages for measurements.

 

[FB.]

Lorelei

Having seen the diamond, I am surprised to hear that it may be leaking light; it''s very bright, with no noticeable dark areas. Light performance seems to be very good.
It''s a GIA-cert, 1ct, H, VS2 and looking at it face-up, it looks like an "F". Until the doubts over it''s cut quality were raised a couple of hours ago, I would have said that the cut was improving the colour grade by 1-2 levels. If I''d been told that it was only a good cut grade, I would have estimated it to be "F" colour.

I''ll take a closer look at it in coming days and I''ll report back if I reconsider my opinion of the stone.

I''m surprised that the GIA don''t include in their cut-grade calculator, a method to screen-out "steep deeps". It wouldn''t be a difficult addition to the calculations.
However, I notice that if I increase girdle thickness on the GIA calculator by just one level (MED -> -STK and STK-> THK), the grade drops to VG.
The GIA calculator seems to be finding something in the medium girdle thickness that just manages to tip the stone into the Ex cut grade. Perhaps this stone really is skating a fine line with it''s light performance and it all hinges on the girdle.

 

[jet2ks]

Date: 6/30/2009 2:09:39 PM
Author: FB.
jet2ks

But which of the three outputs should be trusted?

GIA - Excellent.
HCA using degrees - Good.
HCA using percentages - Very Good.


I would have thought that the greater number of inputs that go into the GIA calculator would give a more accurate result - especially since the HCA can't seem to grade the same stone consistently, depending on degrees or percentages for measurements.

2nd part first. HCA does grade the same stone consistently. The reason that you get different results is because of how the percentage and angles are arrived at by GIA. The angles are actually measured and then rounded (crown to nearest .2 and pavillion to nearest .5), the percentages are then figured off of the angles, so a little more variance/rounding occurs. When you input the percentages into HCA, it converts back to angles. The discrepancy in scores occurs because of all the different rounding and conversion of numbers. If you enter the same angles, table and depth, you would get the same score every time.

GIA can be trusted to grade within their own parameters. What has happened is that cutters and retailers who are interested in the very best performance have found that GIA's tolerances are a little loose. By sticking to more stringent tolerances, better and more consistent performance can be achieved.

You can look at it like an engine. An engine that runs just fine can be assembled based on a certain level of machining and assembly. That engine can be put into car and run for years with no problem, but would never achieve its full potential. A similar engine, machined and assembled to much tighter tolerances will produce more horsepower and be more efficient--it will just take more attention to detail. Either may work for the family sedan, but which do you want in your race car?

However, I notice that if I increase girdle thickness on the GIA calculator by just one level (MED -> -STK and STK-> THK), the grade drops to VG.
The GIA calculator seems to be finding something in the medium girdle thickness that just manages to tip the stone into the Ex cut grade. Perhaps this stone really is skating a fine line with it's light performance and it all hinges on the girdle.

This is because GIA's range to score excellent for a girdle is Thin to Slightly Thick. A stone with a girdle that falls into Thick range can at best get a cut grade of VG. It is not the girdle's affect on light performance (remember GIA doesn't actually grade that), it is that the measurement now falls outside of the parameters for Excellent.

I'm sure the light performance for this stone is very good, it is probably a B+/A- performer, it will just probably not be an A+ performer. In the majority of situations, you may never know the difference. If you could compare this stone to a "superideal" such as a ACA or Infinity, there would be some lighting environments that they would appear very similar and some that it wouldn't quite hold up as well.

 

[FB.]

Thanks, jet2ks.

As you say; the stone is probably a B+, since it appears to perform well.
I''ll also take into account the outputs from the HCA when choosing diamonds in future, in conjunction with the GIA estimator, the well-documented ideal ranges and, of course, the mk1 eyeball.
Part of my reason for joining this forum was to take my diamond knowledge to a higher level - I''ve been a lurker for a few weeks.
Fortunately, "her" diamond collection has only been building for several years and I''d hope to continue to get her better things as time goes on, although her current stones are not bad by any means.

Why is a man so interested in diamonds? I hear you ask......

Briefly.....

I am a semi-professional investor/collector (apart from being a part-time scientist) and I like to periodically sell a few investments to "take a little profit off the table" and put it into something tangible and enjoyable.
I know that there is a sizeable and instant depreciation on gems and metals, but the lifetime of enjoyment is more than adequate compensation for the loss of re-sale value.

 

[jet2ks]

Date: 6/30/2009 4:13:16 PM
Author: FB.
Thanks, jet2ks.

Why is a man so interested in diamonds? I hear you ask......

You are very welcome. We all started somewhere, and I was where you are now at not that long ago. When doing your calculations, do keep in mind that HCA was designed to help do initial screening of stones, as Lorelei mentioned, its calculations are not absolute. Anything scoring under 2 has a high probability of performing well, not a certainty. There are also some stones that score higher that perform well, but a lesser percentage of the whole.

And I didn''t ask, for good reason.

 

[FB.]

She gets to wear them. I get to enjoy the sparkle when we go out for dinner.

I am not a believer in jewellery for men, but that's everyone's freedom of choice and I know that many men wear some jewllery.
About the nearest thing to jewellery that I wear is my watch (and I only wear it a couple of days a week). I even insisted that my watch had no precious metal content (when I bought it, yellow gold or yellow gold trim was popular for middle-of-the-range watches). I don't think that jewellery looks good on men. Besides, the picture above my username isn't a million miles from my (very un-feminine) appearance.

 

[Lorelei]

Jet explained everything really well and said everything I would have!

 

[Lorelei]

Date: 6/30/2009 2:31:18 PM
Author: FB.
Lorelei

Having seen the diamond, I am surprised to hear that it may be leaking light; it's very bright, with no noticeable dark areas. Light performance seems to be very good.
It's a GIA-cert, 1ct, H, VS2 and looking at it face-up, it looks like an 'F'. Until the doubts over it's cut quality were raised a couple of hours ago, I would have said that the cut was improving the colour grade by 1-2 levels. If I'd been told that it was only a good cut grade, I would have estimated it to be 'F' colour.

I'll take a closer look at it in coming days and I'll report back if I reconsider my opinion of the stone.

I'm surprised that the GIA don't include in their cut-grade calculator, a method to screen-out 'steep deeps'. It wouldn't be a difficult addition to the calculations.
However, I notice that if I increase girdle thickness on the GIA calculator by just one level (MED -> -STK and STK-> THK), the grade drops to VG.
The GIA calculator seems to be finding something in the medium girdle thickness that just manages to tip the stone into the Ex cut grade. Perhaps this stone really is skating a fine line with it's light performance and it all hinges on the girdle.

The angles could be in reality a little more shallow than the ones on the report, so that might make a difference to any light leakage, but the main thing is that it is pleasing to your own eyes. Also leakage doesn't always show in all lighting conditions, but it sounds like you have a pretty stone.

I will post a thread of Pricescoper Kelli's ( I don't think she will mind as she often posts it herself in order to teach), she had this diamond recut as it had steep deep angles and showed leakage in some lights. It wasn't noticeable all the time, only in some lighting conditions, she had it recut by Brian Gavin which did away with the leakage. The photos are the ' befores' and if you look at some you can see a dark ring/ dark patches around the table.

Here you go, this page shows the leakage in the diamond prior to recutting.

https://www.pricescope.com/community/threads/loads-of-pics-finally-1-44-ct-rb-i-vs2.91304/page-3

 

[FB.]

I'll report back ASAP once I've fully inspected the diamond. The angles on the GIA report are nominally the same as the dark-centred stone in the link.


What a pity, if GIA's cut grading system is flawed. Their website makes it sound as if almost a lifetime of research and millions of observations went into it's design.
It all sounds so good.

Lifted from the GIA website:

"...access GIA's database of more than 38.5 million diamond proportion sets in order to estimate the cut grade for any standard round brilliant diamond in the GIA D-to-Z color range and Flawless-to-I3 clarity range....."


and lifted from a different page:

"....Cut quality incorporates the aspects of face-up appearance, design, and craftsmanship......"

That sounds as if the GIA grader(s) also apply an element of what they see towards the cut grade. Do you know if that's the case, or am I misinterpreting a statement from GIA?

..............

The more I learn about diamonds, the more it feels as if GIA interpretations (and many other lab interpretations) are just expensive pieces of toilet paper - and that only AGS reports are worthy of a quick skim-read while waiting for the chance to put the GIA paper to good use.....

..............


Apologies to the thread starter for the hijack, but hopefully there has been some good discussion that will benefit them.

 

[orymd]

Well, I am gladd I got an interesting debate going.... I saw the 1.49 ring and it is stunning. It is triple excellent and has a 59% table. Don''t know about the other stuff but purchased it anyway.... I think she will love it. I will post pics after I propose on the 6th.
Thanks for everyones'' help!

Ory

 

[jet2ks]

Date: 6/30/2009 9:31:45 PM
Author: orymd
Well, I am gladd I got an interesting debate going.... I saw the 1.49 ring and it is stunning. It is triple excellent and has a 59% table. Don''t know about the other stuff but purchased it anyway.... I think she will love it. I will post pics after I propose on the 6th.
Thanks for everyones'' help!

Ory

Sorry for the threadjack, ory.

Glad you liked the ring. Look forward to pics.

 

[Lorelei]

Date: 6/30/2009 8:06:18 PM
Author: FB.

I''ll report back ASAP once I''ve fully inspected the diamond. The angles on the GIA report are nominally the same as the dark-centred stone in the link.


What a pity, if GIA''s cut grading system is flawed. Their website makes it sound as if almost a lifetime of research and millions of observations went into it''s design.
It all sounds so good.

Lifted from the GIA website:

''...access GIA''s database of more than 38.5 million diamond proportion sets in order to estimate the cut grade for any standard round brilliant diamond in the GIA D-to-Z color range and Flawless-to-I3 clarity range.....''


and lifted from a different page:

''....Cut quality incorporates the aspects of face-up appearance, design, and craftsmanship......''

That sounds as if the GIA grader(s) also apply an element of what they see towards the cut grade. Do you know if that''s the case, or am I misinterpreting a statement from GIA?

..............

The more I learn about diamonds, the more it feels as if GIA interpretations (and many other lab interpretations) are just expensive pieces of toilet paper - and that only AGS reports are worthy of a quick skim-read while waiting for the chance to put the GIA paper to good use.....

..............


Apologies to the thread starter for the hijack, but hopefully there has been some good discussion that will benefit them.

FB, you might find this thread interesting reading

https://www.pricescope.com/community/threads/gia-ex-let-the-buyer-beware.41371/

 

[Lorelei]

Date: 6/30/2009 9:46:48 PM
Author: jet2ks

Date: 6/30/2009 9:31:45 PM
Author: orymd
Well, I am gladd I got an interesting debate going.... I saw the 1.49 ring and it is stunning. It is triple excellent and has a 59% table. Don''t know about the other stuff but purchased it anyway.... I think she will love it. I will post pics after I propose on the 6th.
Thanks for everyones'' help!

Ory

Sorry for the threadjack, ory.

Glad you liked the ring. Look forward to pics.

Ditto, my apologies too for the threadjack ory, MANY congrats on your purchase and please post some pics when you get the ring!

1.49 from Tiffany is major!!!!

 

[FB.]

Lorelei

Thank you for the link to the discussion of GIA. I am not surprised by what is being said. In recent weeks, I had begun to have some concerns regarding GIA-graded stones as I explored further into diamonds. As a scientist myself, I am aware of how boundaries and statistics are sometimes tweaked to get the results that people want to see.

Having given more thought to the GIA system - compared to the AGS and HCA system - I am now much more wary of GIA and I might, in principle, never buy a GIA-graded stone again. I can see the incentive for cutters to create "steep-deep" stones that may grade higher on paper than their true "eyeball" performance.

For my next diamond purchase, I will seek out an AGS-cert stone. It''s all about principles.

 

[FB.]

I''ve just spent a while looking at the GIA-cert Ex.cut discussed above.

Details here:
Table: 56%
Crown angle: 35.5''
Pavilion angle: 41.2''
Star: 55%
Lower half: 75%
Girdle min: med
Girdle max: slightly thick
Culet: none
Polish: ex
Symmetry: ex
Total depth: 62.8%
GIA estimated cut grade: Excellent.


My conclusion:
I can''t see any significant signs of light leakage and I''ve just looked at the stone in a variety of light conditions and form many different angles. I guess it''s one that sits on the low end of EX/ high end of VG for it''s light handling properties.

 

[Lorelei]

Date: 7/1/2009 6:33:38 AM
Author: FB.

I''ve just spent a while looking at the GIA-cert Ex.cut discussed above.

Details here:
Table: 56%
Crown angle: 35.5''
Pavilion angle: 41.2''
Star: 55%
Lower half: 75%
Girdle min: med
Girdle max: slightly thick
Culet: none
Polish: ex
Symmetry: ex
Total depth: 62.8%

GIA estimated cut grade: Excellent.


My conclusion:
I can''t see any significant signs of light leakage and I''ve just looked at the stone in a variety of light conditions and form many different angles. I guess it''s one that sits on the low end of EX/ high end of VG for it''s light handling properties.

It could be that you aren''t noticing much leakage which is good. If you are really getting interested in this, then you could buy an ASET scope and then you have it for any future diamond purchases. The ASET scope can show leakage like Idealscope but also breaks down the light coming from the diamond into colour codes, so it is a very useful tool to have and it is also great for fancy shapes.

http://www.ideal-scope.com/cart_zoom_item.asp?Id=23&ShowAdd=Y

 

[Lorelei]

Date: 7/1/2009 5:30:37 AM
Author: FB.
Lorelei

Thank you for the link to the discussion of GIA. I am not surprised by what is being said. In recent weeks, I had begun to have some concerns regarding GIA-graded stones as I explored further into diamonds. As a scientist myself, I am aware of how boundaries and statistics are sometimes tweaked to get the results that people want to see.

Having given more thought to the GIA system - compared to the AGS and HCA system - I am now much more wary of GIA and I might, in principle, never buy a GIA-graded stone again. I can see the incentive for cutters to create ''steep-deep'' stones that may grade higher on paper than their true ''eyeball'' performance.

For my next diamond purchase, I will seek out an AGS-cert stone. It''s all about principles.

You are welcome! There are great GIA Excellents out there, it is just a case of choosing carefully. Also you have probably read how the numbers are rounded which further muddies the waters, but if you choose with care with supporting ASET and Idealscope images to determine how well the proportions work together, then you can find some nice stones within this grade.