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kenny

kenny

Super_Ideal_Rock
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Apr 30, 2005
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I've been looking for about a month here.

I'm learning a pitfall of diamond education is you get very particular.
Buying over the internet is tough.
You can't see the stones, so I am trying to learn all the parameters.

Here is my goal:
Round
Perfectly even and symetrical H&A pattern.
Minimum leakage in Idealscope / Firescope image.
E or F, VVS2 or VS1
HCA 0.7 or better, Ex Ex Ex Ex for both AGS and Sarin numbers.
A medium girdle with no flaws touching it or too near it, since it is going into a tension setting.
I'd prefer a crown angle towards the higher side of the range, as I would be happy to trade off some brilliance to get more fire.
Flouresence none or negligible.

The size is what I am most flexible on, this is very unusual I know.
0.7 to 1.2 ct.
So the cut is most important, the size is least importnat.
Color and clarity I'm a little flexible on.
It will be in platinum so I don't want to see any yellow when I look through the side.

Please post responses here.
 
You forgot to list one of the most important things...

Budget??
 
Or that other pesky C known as Cost!!
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I didn''t mention budget because it will be commensurate with the size, clarity and color of the stone.

For a 1.2 ct. E, VVS2 I have would have one budget.

This same budget wouldn''t apply if my dream stone turns out to be a 0.7 ct., F, VS2.

Each budget can be found with a quick PS search.
 
Either Gelin & Abaci and Steven Kretchmer will inspect stone within my review period.
 
Date: 5/28/2005 3:39:12 PM
Author:kenny

HCA 0.7 or better, Ex Ex Ex Ex for both AGS and Sarin numbers.
Click to expand...
.7 or better? Tread cautiously. If you think you're going to get superior optics with .7 or better (lower number) you are mistaken.
 
While what you list is a TALL order, at least you know what you want.

First off, I wanted to address the 4 EX's on the HCA. You are really narrowing down your selections on an already narrow field when you throw this in there. Personally, it's a nice to have all 4 EX's but it's an extra 'perk' IMO. It's hard to find a stone that scores all 4 EX's because the HCA is strict on 'spread'.

That 4th EX on the spread is really from what I have seen, quite elusive AND somewhat more reserved for stones that are more white brilliant with larger spread than fiery which is more aligned with a deeper stone...so you list you want fiery with a higher crown angle, but that means a larger depth rather than a smaller one to get the extra fire...which does not equate to an EX spread...a fiery deeper stone will be a smaller spread, so I don't see you finding a fiery high crown angle EX spread stone. But who knows...you can prove me wrong.
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Also re: the 0.7 on the HCA...that does not actually mean 4 EX's. My husband' stone is a 4 EX stone and it scored a 1.0 on the HCA.

Anyhow, my other point is that sometimes experts don't recommend a score of 0.7 or less on a stone, sometimes they say it can affect scintillation of the stone, therefore not giving you the 'ideal' blend of all the attributes to make a beautiful stone. Brian at WF notes that his ideal HCA score for a well-cut stone would be around 1.0...I usually try to stick as close to 1 without going under by much. I would definitely not focus on a 0.7 or less for my ideal stone.

Anyway just some comments.

I found two stones that may fit your bill somewhat..but not on the 4 EX's or the high crown angle...

http://www.pricescope.com/origin.asp?sh=88&id=706&prc=9385
1.12 F VS1 ACA from WF 1.0 EX on HCA

and

http://www.pricescope.com/origin.asp?sh=88&id=445&prc=6663
.92 F VVS2 H&A from GOG 1.2 EX on HCA

also this one is kind of different but may fit the bill, it also has med blue fluor which would be fun in an F

http://www.pricescope.com/origin.asp?sh=88&id=227&prc=9303
1.05 F VS1 H&A from GOG 1.9 EX on HCA
The thing about this one is that it has that higher crown angle and depth that may have a bit more fire in the stone BUT the pav angle is not adjusted enough to compensate for that higher crown angle, so the HCA score is not as good and the stone may not be as nice as if the pav angle was more like 40.6 to compensate for the higher crown angle...BUT even if you had a 61.7/54/35/40.6 stone in the HCA it would get a 0.9 score BUT it would still not give you that EX on spread. Even a 40.5 angle would still not give that EX on spread even though the HCA is 0.5 (too low for me).

Didn't see anything that had a great blend of crown and pav angle for a fiery look...pickin's are slim right now in this range (e/f vvs-vs) so those were the three that caught my eye but I am more keen on the first two than the last one. But again, think about that HCA score vs fiery stone...the two do not mesh.

So really it could be you have been looking for something that does not exist for the last few weeks, possibly why you are frustrated?
 
Wait a minute... what's the use of piling up ten different grading systems ?

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AGS old cut standard, Sarin which is a measurement device and doesn't have one, HCA with a cutoff that was not meant by the makers, than Bscope, H&A viewer... What am I missing ? There is also Isee2 and DiaGem and probably other dozen or so brilliance guess-timate machines off the list.

These things agree to disagree on the finer points. I don't think the makers cared to insure that any RBC cut model scores the same (top, mid or bottom) an all the gear. So... it sounds like you still need to single out one tool that serves your purpose and go for that.

Locating a H&A round diamond with beautiful brilliance does not take all that much sweat: the're need for some device to identify the H&A pattern because it is not meant to show otherwise. That already insures tight symmetry and proportions well beyond what is visible at all. If the seller uses some other device for cut grading, all for the better.

There are 12 diamonds that meet your criteria on a quick serach for H&A D-F, IF-VS1, 0.7-1.1cts: priced from 4k to 20k.

Three more H&A surface at Exceldiamonds (not listed on the "Search by cut quality" here). All E-F, VS1 0.8-0.9cts and about 5k.

For what my 0.2 worth counts, I am too practical to be a fan of VVS, thinking that the first unavoidable chip after few months or so of wear would downgrade that ! That an expensive chip... In the weight range you mention, something close to 0.9cts sounds great to me, because the size looks very much like 1 carat for allot less cash. Even without a buget that sounds good
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Keeping these points in mind, 0.88cts E-VS1 H&A sounds particularly good.


Hope this helps a bit
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Thank you for the responses so far.
Valeria, I see your point.
Too many tools.
As an ignorant customer it is really tough to see through the hype.
I'm trying though.
I didn't make up all these tools.
I'm just trying to learn and make the best educated choice.

Mara, thanks for the perspective on the low HCA obsession.
I'll cool it.
FYI, I came up with the 0.7 by doing a huge search for all the ideal cuts on PS.
Then I sorted on HCA and I think 0.7 was the highest score with 4 Xs.

Now about that GOG 0.92 ct VVS2 F:
The PS link you posted works but if I just to to goodoldgold.com the diamond does not exist in either the price list or in the other list.
Might this mean it is sold and PS didn't get the update?
 
Date: 5/28/2005 4:55:45 PM
Author: kenny

it is really tough to see through the hype.
Click to expand...
I know....
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Have you seen this thing ?
 
kenny it could be a few reasons, one that it is sold and PS was not updated yet, or that it''s new and it has not been listed on Rhino''s site yet but is in the database, or maybe another reason, I''d give GOG a call and ask them. I know the GOG site is still being worked on as well.

I really like that Solasfera that Val posted even though it''s not my idea of a true H&A...but the BS results are off the chart and the LS image is blood red.
 
Oh no.
Just as my brain was about to explode I find out about Solasfera, diamonds cut with 91 facets instead of 58.

Oh man, will this never end?

Now, why, if you can get off-the-chart GEMEX performance and astonishing Ideascope light leakage performance and two extra hearts and arrows to boot would anyone buy those old yucky 58-facet dinosaurs?

I''m being silly, but really they look great.
Seems like 8* performance.
Has anyone seen an 8* next to a Solasfera?
 
Wellll it's not as easy as saying...oh look at the BScope and LS image and let's get it.

A stone with 91 facets, or 100, or 65 like the Leo or any higher-faceted stone is going to have a different LOOK to it than a 58 facet diamond. I have seen Leo's in person, they are very pretty but to me the stone is like chaos inside...my eye cannot focus on anything because the facets are TOO scintillating if that makes any sense.

There is a reason that the high majority of the round diamond buyers are still buying the standard 58 faceted stones...and why the higher-faceted stones (and there are alot of them out there, different brands) have not caught on..and are more like a small niche market. An 8* is a 58 faceted stone that is exceptionally cut, and some say that some exceptional H&A unbranded stones can rival an 8*, some disagree...but an 8* would not have that same type of sparkle as a Leo or a Solasfera because of the facet difference.

So unless you can see one of them in person to see if you really like it, and maybe compare it to a similarly well-cut 58 facet round brilliant, I would not advise just flat out buying it...because it does not look like a 'regular' well-cut diamond will.
 
agree with most of what mara said on this thread.
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i would prefer a hca score of 1.0-1.5 range for my TIC. any stone with a hca score of < 1.0 might be too shallow for my taste. JMO
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Date: 5/28/2005 3:39:12 PM
Author:kenny
Here is my goal:
Round
Perfectly even and symetrical H&A pattern.
Minimum leakage in Idealscope / Firescope image.
E or F, VVS2 or VS1
HCA 0.7 or better, Ex Ex Ex Ex for both AGS and Sarin numbers.
A medium girdle with no flaws touching it or too near it, since it is going into a tension setting.
I''d prefer a crown angle towards the higher side of the range, as I would be happy to trade off some brilliance to get more fire.
Flouresence none or negligible.

The size is what I am most flexible on, this is very unusual I know.
0.7 to 1.2 ct.
Click to expand...
Kenny,

1) Having used the search by cut utility, and your parameters, I think you may want to make friends with Jim and DCD, as he has three options you may want to review, including this, this, and this one.

2) Regarding the cacophony about HCA, I have recently supplicated Garry to clarify his thoughts on this very matter, and hope he may consider doing so soon.

Cheers,
 
Help me understand what spread is.
I have read everyone's explanation and I still can't wrap my brain around it.

Let me try this:
Is spread just diameter per carat?
Or rephrased, how wide the diamond is for a given weight?
If so, a shallow stone will rate a better spread than a deep stone.
Do I have this right?

If so, then I don't give a hoot about getting HCA= Ex Ex Ex Ex because just want the best optical performance I can find in a stone.
I have already said I am cool with a stone as small as 0.7 ct.
Having the stone look as large as possible for the weight or for the price doesn't matter to me.

Or is spread some optical property that varies with how it well the stone was cut?
 
Maybe Garry will give the specifics on the HCA''s "spread" grade.

To my eye, if two stones have a same diameter the one with the bigger table will look bigger i.e. bigger spread. The sellers of the superideal will tell you that a stone with excellent edge-to-edge light return will face up larger than a lesser performer of the same diameter. I''m not sure if this would be characterized as a bigger spread or not.
 
here is a great quickie tutorial on spread: http://www.preciousmetals.com.au/Tutorial/t_spread.htm

the HCA rewards stones that have literally an 'excellent' spread for their size. that does not necessarily mean a stone that looks like what a well-cut stone should in terms of spread. to me that would be rated VG. but if a diamond looks a tiny bit bigger than it should, for example due to a slightly more shallow pavilion (aka 59.9 or 60.2) with a corresponding table and pav/crown angles, then it would rate that additional EX on the HCA. i have found it very elusive and have learned that getting all 4 ex's is a perk and not a requirement for a stunning stone.

all of those diamonds that regular guy posted have very shallow pavilions with corresponding low pav and crown angles to make them rate all EX and low on the HCA. but i probably would not consider any of those diamonds for myself except the one that scored 0.7 on the HCA and maybe then not even depending what my other options are. again, some say the lower the HCA score...does not mean better and you may lose some scintillation. on one of those DCD stones, the girdle is v.thin-thin which is not desirable for me in an e-ring ESP a tension set. however those stones would probably make fabulous earrings, very white and bright and sparkly.

one thing to note as well is that each person has their own idea of what looks beautiful. personally for me having seen a few stones in person, i know what numbers i am looking for in a stone. but someone else may like a more shallow brilliant stone or a more fiery, deeper stone. it's a very personal choice...

have you looked at alot of diamonds in person? do you know if you like more fire, more white brilliance or do you want the best combo of both? i learned i want the best combo of both, having had a more shallow stone and then having purchased my husband's ACA stone which just knocked my socks off. after purchasing a few more diamonds...now i have my own set of numbers that i buy by.

here is what i would be looking for if i wanted that great blend of both:
table: 54-56%
depth: 60.2-61%
crown angle: 34.3-34.8
pav angle: 40.5-40.7 (maybe 40.8)
thin-med girdle, or med girdle
pointed or no culet

that is my blend of 'perfect' requirements that suits me. not every combo of #'s within that range is going to suit...but it's a good way for me to weed out the chaff and know what my options are. it's pretty strict and only a tiny area of what is considered AGS0.

so i guess the Q is...what suits you?? it's pretty overwhelming isn't it?! don't get discouraged, you will figure it out.
 
Date: 5/29/2005 3:54:09 AM
Author: Mara

one thing to note as well is that each person has their own idea of what looks beautiful. [...]

so i guess the Q is...what suits you?? it's pretty overwhelming isn't it?! don't get discouraged, you will figure it out.
Click to expand...
Yeah! You've got a good chunk of Pricescope wisedom on this thread... and, well, I think Mara's two words cited above sum it up rather well.

There's a laudry list of details everyone decides to consider important and look for, and that is a matter of eductaed guess. It is harder to line up enough diamonds to learn from experience and this is what you get instead !

Oh well... it is hard and perhaps redundant to try and draw a conclusion. This is the time for an executive decission, if you asked me. Just go ahead and do it
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Date: 5/29/2005 12:24:08 PM
Author: phoenixgirl
1.05 F VVS2 0.6 HCA for $9648

1.07 F VS1 0.7 HCA for $7884

1.07 F VS1 0.7 on HCA for $8073

1.12 F VS1 0.6 on HCA for $8656

1.13 F VS1 0.7 on HCA for $9966

These are all the stones listed via ''search by cut'' that meet your criteria out of 25 overall that had ''excellent'' HCA scores. As others have said, I''m not saying these are necessarily better than stones with scores of 1 or 1.3 . . .
Click to expand...
The 4 DCD ones have v.thin or thin girdles which may not work for the tension setting that the OP is considering...the last one from Wink is worth looking into since it doesn''t mention girdle...I don''t see a Sarin link so, kenny, I''d ask for more info on that one.

But again, I''d ask you to let us know what the top priority is....I know it''s not size, and you said it is ''cut''....but is it a superideal TIC cut like a branded H&A as you mentioned up above, or a BIC or a FIC which may be slightly out of the ''ideal'' numbers but with a more specific look? you already noted you do not have to have the 4 EX''s which helps...but I''m still unclear as to what is the most important thing for you ''within'' cut.
 
I really appreciate the time you are all taking to be so helpful to me.
No Mara, I have not looked at many stones.
So I don't have experience on how these different cut parameters actually change the look of the stone.
I need to get out there and just look and look.
I have learned tons here and elsewhere, perhaps too much to the point of having analysis paralysis.

Major development:
I also looked at the Pricescope's Price Statistics section.
It averages the prices of all stones in the PS database and sorts them based on cut, size and clarity.
What a wonderful feature!

I compared two hypothetical stones, both H&A Round, F, VVS2.
A 0.999 carat costs an average of $7242 per carat.
A 1.000 carat costs an average of $9421 per carat.
There is only .001 carat difference so they look identical, but the price difference is $2179.
$2179 just to *say* I have a 1 carat stone?
Uhmm, No thanks.
Also I'd like to do my part as a consumer to express demand for 0.999 ct stones.

Mara asked:
"But again, I'd ask you to let us know what the top priority is....I know it's not size, and you said it is 'cut'....but is it a superideal TIC cut like a branded H&A as you mentioned up above, or a BIC or a FIC which may be slightly out of the 'ideal' numbers but with a more specific look? you already noted you do not have to have the 4 EX's which helps...but I'm still unclear as to what is the most important thing for you 'within' cut."

Actually what I want is evolving as I learn.
I thought I did, but I'm learning that what I wanted was based on ignorance.
I like fire, color sparkle.
But I have HCAitis.
I was stuck on HCAs under 0.7.
Now I'm stuck on HCAs near 1.0.

So if I want maximum fire should I be looking for a stone that is FIC, Firey Ideal Cut?
If so does it have a particular HCA range?
Or, instead of paying attention only to the HCA number, do I look on the graph for a stone that is towards the lower right of the AGS 0 rectangle?
Or do I still shoot for and HCA near 1.0 but pay attention to a pavilion angle that is towards the high side of the range. (Then since the HCA will still be near 1.0 the crown angle will have been cut to compensate for the high pavilion angle.)
Right?

I feel like I am on a Diamond Safari hunting for an elusive game.
 
Date: 5/29/2005 3:05:05 PM
Author: kenny


I honestly don't know what I want.

I like fire, color sparkle.

But I have HCAitis.
Click to expand...


Feel free to hate me for fighting any chance of a simple answer to that rather complex demand
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It is not my fault that honest people make it their job to research diamond optics. That tricky fire thing made even more ink flow than light return.


In theory, the HCA catches one of the zillion factors that add up to make a diamond look "fiery" more often than others. (read here).

"The Tolkowsky Ideal Cuts (TIC) combine a balance of fire and brilliance, but diamonds close to Tolkowsky proportions command a price premium. So again when given the choice it has been my experience that BIC’s have the most demand.

This is rather fortuitous because the yields on BIC are better than the other two types of ideal cuts. In fact FIC’s are few and far between.

BIC Brilliant Ideal Cut Crown angle is less than 32.5°
TIC Tolkowsky Ideal Cut Crown angles between 32.5° and 35.5°
FIC Firey Ideal Cut Crown angle is more than 35.5° "

bic.gif
fic.gif



However, those angles leave lots of facets unaccounted for - and these many "minor facets" have their say as well:

I know this doesn't make things any clearer... Perhaps Jonathan can do that. See his last post on this thread... the relevant hint is:

"The results of my study with the B'scope on the minor facets made me conclude that lengthening the lower girdles increases fire and scintillation in a properly cut diamond ... and that GIA released this same information in their article on DCLR (dispersed colored light return)"
According to this, those rounds with thin arrows (if any) are fiery despite non FIC parameters. Considering some branded rounds cut with extra long lowe girdles (Lazare Kaplan and Solasfera), this rings true as well.


To make things very simple, listen ( = search posts) to David Atlas, "fire" is not even a property of the cut, but some effect that depends more on lighting conditions than the diamond itself.

Sorry for the mess...
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First off, a FIC will not look the same as a TIC. Just as a BIC will not look the same as either a FIC or TIC etc.

So that''s why I asked if you had seen diamonds in person to know what you really want to see in your stone. I had a BIC stone which sparkled very whitely and was stunning in a very white sort of way. It didn''t have that much fire going on inside the stone. Over time I noticed in certain lighting situations it just didn''t pop at all, while in other''s it was stunning. My next stone was a TIC H&A and I absolutely was smitten by how excellent it looked in the same lighting situations that my old stone didn''t spark in. I have not seen a FIC but I would imagine that it would excel in some situations and not in others, much as BIC did. For me the TIC is the best of both worlds, but some people really love a BIC or FIC look. However, if you are not sure what they look like to say Oh yes that is what I am looking for...I would almost say that a TIC is ''safest''?

Anyway, assuming you wanted a FIC...here is an example of specs you may look for:
Depth: 63%
Table: 54%
Crown A: 35.7
Pav A: 40.4

Result: 1.0 EX on HCA BUT spread is only Good while the other three are EX. So as you can see, getting a FIC may not be in alignment with the original req of 4 EX''s as the depth of a FIC will most likely hide some weight in the pav and take away that EX on spread.

Anyhow that is just one combination of numbers that will result in a FIC type of stone. You can play around with the HCA yourself, plugging in #''s etc to see what kind of combinations return desirable results.

Then the hard part is to actually FIND a well-cut FIC stone!!! We have only seen one or two on here, I think both of them were purchased from Blue Nile.

Just some additional food for thought.
 
here is another image from Garry's tutorial on the HCA re: FIC and BIC...

as you can see, shallower crown angles, larger tables, shallower depths and higher pavilions are more BIC and smaller tables, larger depths, steeper crown angles and smaller pav's make for more FIC's.

it's a very fine line finding a BIC or FIC that will POP as opposed to be dull, IMO using the HCA and the IdealScope/LightScope to gauge light return would be my top two tools in finding one of those more elusive beauties.

oh and the red circle around the image below is the HCA's ideal area of numbers.

ghideal.gif
 
Kenny,

Constraining your options on the search by cut database here, this is another option you might want to look at (plus 3 others closer to .7 in size at half the price). An advantage with this .92 VVS2 from GOG is that Jonathan there is well trained to talk to you about lower girdle lengths, and their impacts and such, as Ana mentioned.

Though Garry marks out the geography of BIC, TIC & FIC, and further, though I did buy an FIC...as Mara mentions... there is reasonable question about the value of even discussing them, because unless you have a very talented vendor willing to look high and low for you (I found mine accidentally, when not looking for it, on the Quick Search here, where options are presented specifically without helpful cut detail), they are virtually impossible to find.

Mara''s points earlier about the need to attend to girdle width seem prudent, given your intention, and I think all of those appearing now on the aforementioned database would be fine, probably, but I''m no expert.

Best,
 
Have not got time to read all this

I think i can summarise by saying that HCA 0 involves trade off''s
What many people believe is the very best cut has a spread penalty of around 0.40 - so going too low can be bad (depending on your beliefs).

Of course many people might change their mind if anyone ever bothers to study the dirty diamond affair.
(feeling like intrigue as i am staying in an hotel where some watergate s..t happened)


Have never been supplicated before Ira - I think it feels good, but it would help if I knew what it was ;-)
BTW your museum is cool mate
 
kenny did you ever buy anything? what''s going on?
 
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