Advice on this stone?

[JayTee]

This site has been tremendously helpful to me in terms of all the information I've absorbed both from the tutorials as well as the people on the forums. I also appreciate that people are honest about where they come from, what they prefer, and if they are zealous supporters of any one type or standard.

This is especially true considering the amount of conflicting and confusing info I've gotten from people at B&M's I've visited. There was this one lady (who was really sweet) but she kept trying to push a stone which was GIA Ex-Ex, saying that Ex-Ex ratings are really rare, she hasn't seen too many of them (and she says she's been in the business for 20 years). I go log on right afterwards and see quite a few stones with that rating. hmm.

That in mind, I've narrowed my search down to a few stones (trying to propose before the end of the year) and I was wondering if anyone had any advice on this particular stone. Also, I've read other posts where pictures of stones were posted using something called DiamCalc? How can I get this done for the stones I'm looking at?

Stone details:
RB
7.20 - 7.23 x 4.32 mm
1.37 carat
Depth% 59.9
Table% 60
Crown angle 32.9
Pavilion angle 41.2
Girdle Med to thick, faceted
Culet None
Polish Ex
Symmetry VG
D VS2

I put the numbers into the HCA and got a 1.8 score, which seems to be pretty good (within TIC), but in comparing these numbers in some other indexes (AGA, Blue Nile), it doesn't seem to be a true "ideal" cut stone.

And yes, I've already seen the stone, but I don't trust my eyes too much, since pretty much all of the stones I've seen have been shiny and sparkly

Any help would be appreciated.

 

[Mara]

Ran the #'s you gave through HCA and it got a 1.8 TIC which is pretty good! The thing I noted is that it gave Fire, Scint and Brilliance all VG's but the Excellent was Spread...which means that your 1.37c diamond will LOOK larger than it really is, which is always great. My diamond is very similar, it has a spread of around .13 carat..ooh la la!

My opinion is you can keep searching for an 'ideal'if you want, but if you love this stone, and it speaks to you--since on paper it looks pretty good..at this point its more about your eyes and what you think.

Just out of curiousity..could you let us know what price you have been quoted? If you mind..don't worry about it

Also maybe if you are really nice to him..Leonid will do some DiamCalc mockups of your diamond too. It'll tell you the spread amount too, which I'd love to see!

 

[JayTee]

Thanks Mara! I guess at this point, I'm looking for a little reassurance -- aren't we all? Nice to know that it will look larger than it really is, so I'll tell my girlfriend to keep showing it off.

The price I was quoted on the stone was $9090 -- it sounds reasonable, but since its at a B&M, I'm going get dinged on sales tax

But I am going to see the stone again this afternoon, so I'll definitely be taking a closer look at it with my limited eyesight.

 

[Mara]

JT--try a little negotiation with the jeweler, you never know! Maybe offer them $8500 and see what they say...even if they say $8700 then your tax ends up being less. If you haven't tried negotiating yet you probably have some leverage.

Ran a quickie Pricescope search on diamonds similar to yours and it looks like you got a great deal! Add in the 'spread' which is always nice...

now where is Leonid with that DiamCalc jpg??!

 

[JayTee]

So I just went to another jeweler, and now I'm torn

This jeweler personally was excellent. Although the stones she was showing me were above the price range I was looking at, she took the time to look at the information I had for the other stones at other stores and helped go through them with me and gave her advice on which one she would choose. I think that is extremely nice for anyone in any industry. She gave me a 1 hour class prior to even looking at any stones to explain all the terminology and what the stones looked like, with color range and asking me to look at these stones under a special gem microscope (there's some sort of dark light underneath that brings out the inclusions) -- don't know what it was called, but it was GIA branded.

However, she wasn't too hot about the D VS2 that I mentioned above. With her definitions, she considered it not an "Ideal" Cut stone (her Ideal dimensions were pretty close to Tolkowsky, I think, 60-62.9% Depth, and 53-57% Table). She recommended this stone (which was not hers either) instead:

1.26 F VS1
Depth % 60.7
Table % 56.0
Crown angle 34.7
Pavilion angle 40.7
Girdle thin
medium blue fluoresence
$8686
AGS0

I unfortunately do not have the actual dimensions for this other stone, because at that other store, the salesperson didn't seem too happy I was writing all this information off of the certificate, so I rushed.

Can anyone provide any advice? I know that I'm really splitting hairs at this point, but I just want to make sure that I get the best for my lady. Now I'm just torn.

 

[Mara]

It's always great to work with a jeweler who gives education as well as information. The stone you originally mentioned (D, VS2) is not necessarily what some people would consider 'ideal', but it depends on how it looks with your eyes. The second stone (F, VS) gets a .8 TIC on the HCA, with all EX's and Spread being VG. Your first stone had all VG's with the Spread being excellent.

Having seen the two diamonds in person, does one appear to be more sparkly or fiery than the other? Can you actually see a difference in the 'size' of the diamond (since with the spread of the first one it might appear to be larger than a 1.37)? What are your priorities--e.g. best cut for the $$ regardless of size, or are you trying to find a great combo of cut and carat for your budget? That will go a long way in helping you decide, but both of these stones sound good..though I haven't seen them NOR am I anything remotely close to an expert. Personally, for the first stone (D color 1.37c) I thought the first deal was pretty good, plus you get the extra 'spread' for the $$. I like spread!

Anyhow the one other piece of info I will impart is that when we bought our stone we knew its flaws (it has a 61.4% table and a shallow 29.9 crown). People who heard about it and hadn't seen it (e.g appraiser) completely warned us against it etc..but when the appraiser finally saw it, she was surprisingly shocked (in a good way). She said it was nothing that she might have thought from the proportions (she thought it might be a swindle or fish-eye), and that it was a great stone, with tons of sparkle and brilliance. So if this jeweler who helped you out today hasn't actually seen the 2 stones, it might be hard for her to make a judgement call based on JUST the numbers. That is something we definitely learned about during our quest.

If you are truly torn between the two, what about taking them to an independent appraiser to see what they think? This might help make the decision for you.

You didn't mention polish or symmetry on the second stone? Also, the medium blue fluor might not be the best thing in some people's opinions, though you can run some searches on past topics to see different trains of thought on medium to strong fluorescence in a stone and make your own judgement.

Best of luck..it's a tough decision, and even after you make it, there is no guarantee your mind will be set at ease..ours wasn't. It wasn't until we actually had the stone in our posession and looked at it again (in the stores sometimes you can feel a little pressured) for as long as we wanted, and in different lighting conditions, did we realize just what a beauty it was and what a great decision we'd made under pressure. So sometimes its a leap of faith, you can eduate yourself as well as you see fit, and then make an educated decision and hope for the best! Chances are it will turn out fine..from what I can tell these two stones both sound fine...now you just have to make the decision!

Any of the experts want to weigh in on the two stones?

Okay I am off to decorate the Xmas tree!

 

[JayTee]

Mara,
Thank you very much for your advice! I really appreciate all the help and perspective that you have provided.

Actually, the two stones are in stores which are right next to each other, and although I doubt that either of them will let me walk over to the other store with the stone for comparison, I think my next step will be to look at the one I like and decide whether it is sparkly or fiery enough for my satisfaction. Plus you can't get any better than the D color on it!

thanks again!

 

[JayTee]

Leonid,
So is there any chance you'd be able to post some idealscope DiamCalc jpgs for these stones (or at least the first one, since I don't have the dimemsions for the second one)? Or are they so similar, there really isn't any point? I guess with the first one, I want to make sure there aren't any light leakage problems or anything of that sort.

Mara told me to ask nicely

Stone #1
1.37 D VS2
7.20 - 7.23 x 4.32 mm
Depth% 59.9
Table% 60
Crown angle 32.9
Pavilion angle 41.2
Girdle Med to thick, faceted
Culet None
Polish Ex
Symmetry VG
Fluorescence None
HCA vg-vg-vg-x 1.8 TIC

Stone #2
1.26 F VS1 AGS000
Depth% 60.7
Table% 56.0
Crown angle 34.7
Pavilion angle 40.7
Girdle thin to med, faceted
Culet None
Polish ID
Symmetry ID
Fluorescence Med Blue
HCA x-x-x-vg 0.8 TIC

Thanks in advance,
JayTee

 

[fire&ice]

Hi ..just wondering who graded the stones? GIA? AGS?

 

[JayTee]

The first stone had a GIA certificate. The second stone was certed by AGS.

 

[pricescope]

JayTee,


[/u]

 

[pricescope]

[/u]

 

[JayTee]

Thank you so much Leonid!

I can't wait to pull these up in GemAdvisor to take a look. I'm actually nervous!

Thanks again.

 

[pricescope]

----------------
I'm actually nervous!
----------------

Don't be Both diamonds should be nice

 

[Mara]

I downloaded the files too and looked at them each, compared them to golfer's file that L did last week, and mine from a few weeks ago.

Out of curiousity..Leonid and other experts, how do you interpret both of JayTee's files..which diamond would you recommend? I see them both having different patterns of brilliance, the second diamond (2) showed better results on the 'cut quality' calculation screen, but only slightly..and I see a bit of a dark table on the first diamond (1), similar to mine. When compared to my picture, it's similar, but my arrows are sharper near the table. Golfer has what appear to be perfect arrows, but if I recall correctly he got an H&A. However one of JayTee's diamonds looks to be slightly more brilliant with light return along the edges than golfer's unless I am mistaken. What does this all MEAN??

 

[JayTee]

CutNut,
Any advice on the two stones?

Actually, any advice on the first stone? (1.37 D VS2) It does reasonably well on your HCA (1.. It does this in spite of having a larger than ideal table size (60%) and a smaller than ideal crown angle (32.9). Is this an example of the two factors offsetting/complementing each other? And how much of a factor does spread play in improving the HCA score (since the stone received an 'Excellent' for Spread but 'VG' in all other areas). Is this stone an example of a non-traditional ideal? *crossing my fingers*

Also, in viewing the Idealscope images that were provided to me by Leonid, I noticed that the table showed quite a bit of light gray/pale pink -- both of which were things that you mentioned should be avoided in the Idealscope portion of your tutorial.

Thanks in advance for any advice.

 

[Serg]

First diamond has "good" contrast only.


"Thus, we have shown that the coefficients used at GIA absolutely do not correlate with the BR coefficient defined intuitively. Moreover, in our imaginary experiment these coefficients almost do not change, while BR changes strongly (first increases and then falls down to almost zero). This example illustrates that the WLR coefficient principally differs from the brilliance, and that WLR measurements do not allow one to study the brilliance. This experiment also shows that the LRMSU coefficient does not correlate with the brilliance as well. However, a multiplicative function of the image contrast and the LRMSU coefficient can be used as a good approximation of the brilliance.

The example considered above is not abstract or far-fetched. It describes rather adequately the brilliance phenomenon perceived by a man looking at a diamond. When no dispersion occurs in the diamond (for example, if the illumination is monochromatic), it acts like a plurality of tiny mirrors. Thus, although the split mirror model is quite simple, it allows us to introduce a correct and adequate definition of primary brilliance. "

Read 3 pages from:

http://www.gemology.ru/cut/english/grading1/8.htm

 

[JayTee]

Serg, thank you for the pointer to the article.

Unfortunately, it is very technical (for me), and even after rereading it a few times, I'm not understanding how the section you pointed me to, explains the role of contrast in brilliance.

And when I clicked on Contrast help in GemAdvisor, it told me that it hasn't been included yet

So when you say that the first stone as "only" good contrast, does that detract from its brilliance? I noticed that GemAdvisor correspondingly gave it an 0.90 (Good-VG).

Thanks again for your help!

 

[Mara]

I think one of an archived post on 'table size' had some info from Leonid or someone saying that when you increase the size of the table, the total depth should decrease. An idea of a non-desirable diamond (IMO) would be similar to a 62% Table, 59% Depth, 32.9 Crown Angle, 41.8 Pav Angle. That nets around a 4.9 on the HCA. But if you take our diamond which is 61.4% Table, 56.9% Depth, 29.9 Crown Angle (a little shallow), 41.1 Pav Angle, it nets a 1.5 on the HCA you will start to see how it works in general.

Increase the table size, decrease the depth and pav angle. On the same original undesirable 4.9HCA scoring diamond, modify the Depth to 58% and the Pav Angle to 41.6 and you get a score of 4.1HCA. Slowly going up. Again decrease that depth to 57% and the Pav Angle to 41.3, now your diamond is a 2.7HCA. Play around with the #'s a bit and you will see what the HCA considers good vs. bad. Large table and large depth bad. Larger table and shallower depth can be good, depending on the factors such as pav, crown angle and culet, etc.

Hope that helps slightly, obviously this isn't a calculation or by any means a mathematical equation in its correctness, but its a general view, larger table should have shallower depth. Larger table and larger depth equal dull stone cut for weight retention and spread vs GOOD CUT.

So if you can find a stone that scores EX on spread and gets under 2.0 on HCA ..which you have, I think that is GREAT..as that is what ours got. Ours got Excellent, VG, VG and Excellent and scored 1.5 on the HCA. We got an extra .13carats of a LOOK out of it, and paid less than a 1.34 stone would have been. Is it IDEAL in the IDEAL sense? Not really, but our appraiser was shocked it was such a great stone. So we lucked out. Sounds like you might too?

 

[Rhino]

Greetings,

Leonid, while what I think you're doing is GREAT it can (even though this is not your intent) also be very misleading to what the client is actually considering or looking at. I viewed the files and if it hasn't been mentioned you should note that the files you provided assumes an incredible level of precision that may simply not exist in the stones he is looking at. A 3 dimensional symmetry that contributes to the beauty of the diamond that may or may not exist in what he is looking at. Personal experience with most of the diamonds being offered on the market says the chances are slim to none however there is the slight chance that I may be wrong but if you change the 3 dimensional symmetry of those stones or alter their minor facets this can change the appearance of the diamond and affect it's brilliance score no matter what machine you put it in.

Just my .02c

Rhino

 

[jkruer01]

What program do you use to read the files that Leonid posted and how can I get that program?

Thanks,

 

[Serg]

----------------
On 12/11/2002 4:34:03 PM

Serg, thank you for the pointer to the article.

Unfortunately, it is very technical (for me), and even after rereading it a few times, I'm not understanding how the section you pointed me to, explains the role of contrast in brilliance.

And when I clicked on Contrast help in GemAdvisor, it told me that it hasn't been included yet

So when you say that the first stone as "only" good contrast, does that detract from its brilliance? I noticed that GemAdvisor correspondingly gave it an 0.90 (Good-VG).

Thanks again for your help!
----------------


JayTee,

You can use below formula for simple approximation of the brilliance.
BrillianceTypeOne=SQRT( LightReturn*Contrast)

 

[Serg]

----------------
On 12/12/2002 7:38:30 AM

What program do you use to read the files that Leonid posted and how can I get that program?

Thanks,
----------------


http://www.cutstudy.com/octonus/english/gemreader/index.htm

 

[JayTee]

Thank you all for all of your advice and kind words!

Serg,
Now that I go back over what you posted, I see exactly what you're referring to (how brilliance is related to contrast). Thanks for pointing that out.

Rhino,
I'm actually aware that what I am doing is viewing a perfectly symmetrical approximation of a stone through the GemAdvisor (as opposed to using an actual Idealscope or other viewer on a the stone itself) but I am taking that into account. My intent in asking Leonid for this information was to see if it would show any glaring problems with light return/light leakage. As I have seen the stone in person, the numbers and calculations can take a correspondingly smaller role in my final decision. (although I find that I do mull over and analyze the information repeatedly

Mara,
I definitely think I'm lucky in finding such a stone. I did as you suggested and played with the numbers of that stone in the HCA, and found that I was apparently just on the edge of very interesting ideal behavior. If I drop the table by 1.5%, Fire goes from "vg" to "ex". If I decrease crown angle by 1 degree, Light Return goes from "vg" to "ex" and the HCA score returns as a 1.5 BIC. (Too bad, that isn't the actual case with this stone)
. In all the graph/charts I've seen (Serg's work, GIA WLR chart), when I plot out the crown angle/pavilion angle, it seems like this stone is right at the border of different rankings as well.
Also, I looked through the archives for your older posts when you first found your stone, and I must say, I really appreciate all the help you have provided, considering that you found yourself in a similar situation when you were looking at your "large" table stone.

So to update you all on my progress, I returned to the store a third time, as I requested to look at this stone under a Gemolite microscope (the salesperson has been wonderfully accomodating, by the way -- where do I post the recommendation? ) This time she also had a 1.31 carat D VS1 AGS0 Ideal in house, which was great for my comparison purposes. The 60% table stone looked fine under the Gemolite (actually quite a clean VS2, only one crystal that I generally notice under the loupe/microscope) but when I compared the two stones side by side is where it got interesting.

The Ideal stone was *slightly* more sparkly (as in it took a minute to decide) But my friend's eyes were able to pick out the Ideal stone as being more sparkly 3 out of 3 times (we kept mixing up the two to try and guess). We both also noticed the darker table of the non-ideal 60% table stone, which I think Mara, you also noticed as a feature of your stone. In the same way, the side facets of the larger stone were quite sparkly in comparison. Another interesting note was that when I got home and plugged the Ideal stone numbers into HCA, it only received a 2.4 score, outside ideal range. Just for kicks, here are the ideal's numbers:

1.31 D VS1 AGS0
Sym Ideal
Pol Ideal
Depth% 61.6
Table% 55
Crown angle 35.7
Pavilion angle 40.8

I think the crown angle may be slightly larger than desired, which may be what penalizes it in the HCA. I'm not actually interested in this stone (outside my budget), but using it as reference.

So in summation (I know I've dragged on quite a bit) -- I'm getting really close to making my final decision. The larger stone remains quite high on my list as I have seen it and I do like how it looks (does it speak to me? dunno, I'm kinda hard of hearing ) The Excellent spread (it does look noticeably larger than other comparable stones) is a definite plus. Given my budget, I've basically decided that unless I can find a true ideal stone on the internet with similar parameters (size and color) within my budget range, I will go with this stone. Maybe it *is* speaking to me. . .but after looking at this many stones, I feel like this:

Thanks again to everyone who's posted in with their knowledge and perspective. I will continue to update and post pictures after I make my decision.

 

[pricescope]

JayTee - terrific post. Thanks so much!

----------------
the salesperson has been wonderfully accomodating, by the way -- where do I post the recommendation? )
----------------Just post the names here.

 

[Mara]

----------------
On 12/12/2002 12:33:43 PM

So to update you all on my progress, I returned to the store a third time, as I requested to look at this stone under a Gemolite microscope (the salesperson has been wonderfully accomodating, by the way -- where do I post the recommendation? ) This time she also had a 1.31 carat D VS1 AGS0 Ideal in house, which was great for my comparison purposes. The 60% table stone looked fine under the Gemolite (actually quite a clean VS2, only one crystal that I generally notice under the loupe/microscope) but when I compared the two stones side by side is where it got interesting.

The Ideal stone was *slightly* more sparkly (as in it took a minute to decide) But my friend's eyes were able to pick out the Ideal stone as being more sparkly 3 out of 3 times (we kept mixing up the two to try and guess). We both also noticed the darker table of the non-ideal 60% table stone, which I think Mara, you also noticed as a feature of your stone. In the same way, the side facets of the larger stone were quite sparkly in comparison. Another interesting note was that when I got home and plugged the Ideal stone numbers into HCA, it only received a 2.4 score, outside ideal range. Just for kicks, here are the ideal's numbers:

So in summation (I know I've dragged on quite a bit) -- I'm getting really close to making my final decision. The larger stone remains quite high on my list as I have seen it and I do like how it looks (does it speak to me? dunno, I'm kinda hard of hearing ) The Excellent spread (it does look noticeably larger than other comparable stones) is a definite plus. Given my budget, I've basically decided that unless I can find a true ideal stone on the internet with similar parameters (size and color) within my budget range, I will go with this stone. Maybe it *is* speaking to me. . .but after looking at this many stones, I feel like this:
----------------


When we were looking at our 61.4% table stone, we also had another stone, a 1.24 E, SI1 ideal cut (1.0 HCA Tolowksy) to compare it so. When compared side by side, the darker table was more evident in our stone, and I personally thought that the other stone (ideal one) looked *slightly* more fiery inside, but no one else agreed, they all said they were the same. But then again I caught the slight dark carbon inclusion on a pav angle with my naked eye and no one else did, so maybe I have wonder woman eyes or something. Anyway--it was a difficult decision when side by side to the other stone, but it was good to see the slight differences and help you really know your stone better if that is what you choose. Later when we owned the stone, and even now sometimes, its hard for me to even see the darker table. So it might be certain lights, or certain angles, but its not all the time. It's interesting, like a chameleon stone!

For whatever reason, we both really liked the larger tabled stone when we first saw it, especially my boyfriend, he really FELT that the stone was the one for us. I thought no way was this stone going to get a good HCA score, figured it'd be a 4 or something horrible. I was relieved when I ran the #'s through the HCA when we got home, that it performed well, but the other stone got a 1.0 and I thought, well that is even better! However, when the two stones were side by side, the larger tabled stone definitely looked larger, and they were technically the same size in carat weight. The diameter of the stone we chose is something like 7.15-7.19 w/4.08 depth. So its more along the lines of the diameter of a 1.35-1.40 carat stone. Because I'm a true 'girl'..I liked the extra spread on the diamond, as we weren't really able to afford to go into the 1.35 carat range and still get the sort of quality we were searching for in color and clarity. My guy liked that too, as he would have loved to get me a bigger stone, but diamonds aren't our top priority for money squandering.

To go back to the darker table bit also, its not as though its a black hole or anything, its just a slightly lightish gray area underneath the table--hardly visible to me and I'm sure that the average joe would never notice it, not with how sparkly the stone is in general. The edges are more sparkly than the ideal stone's edges were..so its much more sparkly and brilliant along the edges. Yours sounds similar.

All in all--I'm very happy with our choice. This is not the only diamond I will ever own, but I couldn't be more pleased with the decision we made on our stone. There is plenty of time for me to own true ideal 'perfection' later if that is what I *really* want then. But for now, this is the stone that we both really loved, who cares if its not ideal cut? The appraiser liked it, she mirrored our thoughts, and strengthened our feelings of making the right decision.

I look at it somewhat along the lines of: we found something that is maybe a little bit more rare than a stone that rates 1.0 TIC on the HCA and fits within the broad AGS 000 spectrum of ideal. AGS rates our stone a SEVEN, a far cry from a 0. But in looks, it knocks our socks off. We know its a stone we are proud of and I know it will look spectacular on my lonely (for now) little hand!

You will make the right decision for you, and maybe even after making the decision, you might second guess it because we are not talking small amounts of $$ here, but in the end, with your superior pricescope education under your belt, you will be happy with the final outcome. Also, your girlfriend will not even know all the agony and ecstacy you went through in choosing the stone for her, all she will see is a huge sparkly rock and you on one knee!

 

[Richard Sherwood]

Hi JT. I just got the DiamondCalc program a week ago, and haven't tried posting pics yet, but I'll give it a shot. Here's the 1.37 (cross your fingers).

Looks pretty good...

Rich, GG
Sarasota Gemological Laboratory

 

[Richard Sherwood]

You didn't give the mm's on the 1.26 F VS1, but I approximated it using the percentages. IdealScope computer generated picture follows.

Another nice stone...

Rich, GG
Sarasota Gemological Laboratory

 

[Richard Sherwood]

Cool, I did it.

Somebody high five me.

 

[Richard Sherwood]

Jonathan makes a good point about the symmetry seldom being like that depicted on DiamondCalc. It's true. The program can't take into account symmetry variations, other than the length of star facets and lower girdle facets.

For the past week though I've checked out every stone I've appraised through the DiamondCalc, and I have to say I'm quite pleased with the overall performance of the computer generated picture with the actual stone. I've been using the IdealScope, comparing it to the rendering, and the "overall" light performance is usually quite close to that of the actual stone.

It reminds me of the HCA. A good help for the armchair diamond shopper, which will generally steer him in the right direction and keep him out of trouble. When you get down to the nitty gritty though, take it to someone who knows what they're looking at. Little things can make a difference.

Rich, GG
Sarasota Gemological Laboratory