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Am I a good Pricesope student?

ParticleMan

Rough_Rock
Joined
Feb 24, 2016
Messages
4
Hi There!
I've been researching for MONTHS through these forums, B&M stores, online videos, ect, educating myself on what I (and my GF) would be most happy with and I'm ready to buy! (And find a good deal!)
I am hoping I can get some feedback on if I'm on the right track with the below diamond? (It's not necessarily the one I will buy, and I don't have an actual picture of it) but I attached the GIA report. I'm looking for something that will be eye clean from 6-10 inches away and will sparkle brighter than most any other rings she would compare it to! It's VS2 so those inclusions shouldn't be an issue right? Any help would be much appreciated!

And thank you to all the posters for the amazing info! :)

Chris
 

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Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,198
What's the HCA?

Round Diamonds 101:

The entire purpose of faceting a diamond is to reflect light.
How well or how poorly a diamond does this determines how beautiful it is.
How well a diamond performs is determined by the angles and cutting. This is why we say cut is king.
No other factor: not color, not clarity has as much of an impact on the appearance of a diamond as its cut. An ideal H will out white a poorly cut F. With round diamonds even a GIA triple Excellent is not enough. And you must stick to GIA and AGS only (HPD in Europe is good as well). EGL is a bad option: [URL='https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/']https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/[/URL]
So how to we ensure that we have the right angles and cutting to get the light performance we want?
https://www.pricescope.com/wiki/diamonds/diamond-cut
Well one method is to start with a GIA Ex, and then apply the HCA to it. YOU DO NOT USE HCA for AGS0 stones generally, though you can. In general, AGS0 trumps HCA though as one examines the actual stone and the other does not.
https://www.pricescope.com/wiki/diamonds/holloway-cut-advisor
The HCA is a rejection tool. Not a selection tool. It uses 4 data points to make a rudimentary call on how the diamond may perform.
If the diamond passes then you know that you are in the right zone in terms of angles for light performance. Under 2 is a pass. Under 2.5-2.1 is a maybe. 2.6 and over is a no. No score 2 and under is better than any other.
Is that enough? Not really.

So what you need is a way to check actual light performance of your actual stone.
That's what an idealscope image does. https://www.pricescope.com/wiki/diamonds/firescope-idealscope
It shows you how and wear your diamond is reflecting light, how well it is going at it, and where you are losing light return. That is why you won't see us recommending Blue Nile, as they do not provide idealscope images for their diamonds. BGD,BE, James Allen, GOG, HPD, ERD and WF do.

The Idealscope is the 'selection tool'. Not the HCA.
So yes, with a GIA stone you need the idealscope images. Or you can buy an idealscope yourself and take it in to the jeweler you are working with to check the stones yourself. Or if you have a good return policy (full refund minimum 7 days) then you can buy the idealscope, buy the stone, and do it at home.

Now if you want to skip all that... stick to AGS0 stones and then all you have to do is pick color and clarity and you know you have a great performing diamond. Because AGS has already done the checking for you. That's why they trade at a premium. Some AGS0's are better than others though, so pay attention to any ASET or IS provided.

In general with rounds, you will want a table 60% or less. A depth between 59 and 62.4. Crown angle 33.5-36. Pavilion Angle: 40.6-41 (there is a little give on this). And the crown and pavilion angles must be complimentary which is what the HCA checks for you.

ON COLOR:

It is important to remember is that color is graded FACE DOWN. Where there is NO light return. Not face up where there is light return and refraction. You wear diamonds set. FACE UP.

Within one color grade, even the labs can't agree on the color grades of stones and something could be a "high" H or a "low" E. So... no. Not really. Within 2 color grades it is hard. Not impossible. But very hard. And it gets harder once set. If you are talking ideal rounds, or any stone with ideal light return and no sharp corners it gets harder still because the ideal light return masks body color.

Generally we say to be conservative stay above H in a round. But MANY people have happily bought white I or even J diamonds when trying to eek out a little more size.

This is how I think of it.

Ever gotten one of those HUGE paint fan decks? Where there are literally 100s of colors of whites? And when they are RIGHT next to each other you can TOTALLY tell that one is bluer/colder and one is a bit warmer and which one is one is TOTALLY warmer. One there's one that's slightly greener. One that's slightly pinker? But really. They are all white?

Then you pick one after agonizing over this white or that white and when it's on the walls and people are like: Oh. You painted again. And it's STILL white. Great.

And you're all... BUT it's BLUE white. Or it's a WARM white now. It used to be ____ white. It's TOTALLY different.

It's like that. You are talking about shades of white. D is colder... J is warmer. But it's all white.

YES. If you have an accurately graded F and an H THAT HAVE THE SAME PERFORMANCE you are going to be able to tell them apart when you compare them. Just like you would be able to tell if you painted your walls a warm white, but painted the crown molding a cold/straight white. But both are STILL white.


I want you notice all the qualifiers thought. I'm talking about stones with the SAME performance. An ideal H will out white an F that has compromised light performance from a poor cut.

NOTHING impacts the appearance of a diamond as much as cut. CUT is king.

You want the shinest whitest and brightest diamond out there: Cut is King. No other factor, not color or clarity or anything else impacts how white bright an shiny a stone is.

ON CLARITY:
http://www.goodoldgold.com/4Cs/Clarity/SI/ and http://www.goodoldgold.com/4Cs/Clarity/VS/ Generally we say that eyeclean SI1 and VS2 are as high as you need to go with round brilliants, have your vendor check the diamond for this. VS1 will always be eyeclean, but they do cost more and an eyeclean SI1 and a VS1 will look the same to the unaided eye. Vs2's are not all eyeclean, though so you do have to get images of the stone and ask the vendor to have their gemologist tell you if it is eyeclean as well.
 

ADN

Shiny_Rock
Trade
Joined
Nov 24, 2015
Messages
311
ParticleMan|1456294133|3994813 said:
Hi There!
...It's VS2 so those inclusions shouldn't be an issue right? Any help would be much appreciated!

And thank you to all the posters for the amazing info! :)

Chris
Hey mate - IMO anyone taking the time to make sure they're getting the best value for money is always a good student :)
I'm in the trade, so I can't comment on stones specifically - but in general, with a VS2 in a round brilliant, they're likely to be eye-clean, so most of the time you won't have any issues from a normal viewing distance.
However...having said that, it really is best if you can at least see an image of it for yourself - or if that's not possible, and if you're comfortable with the vendor, get them to confirm it's eye clean (based on a definition of which you're comfortable with).
Clarity is a range, so you can have top end VS2s (that are borderline VS1s... :dance: )...and bottom end VS2s (borderline SI1s... :doh: ) - there are some centre of the table, solid black inclusions in the VS2 range which may/may not be eye clean, so it's best if you can confirm - - - this is also one reason why, all else being equal, there may be price differences among diamonds of the 'same' VS2 grade.
But overall, I'm a big fan (like I think many PSers are ;-) ) of the SI1/VS2 range as you can get some really beautiful eye clean stones.
Hope this helps
 

ParticleMan

Rough_Rock
Joined
Feb 24, 2016
Messages
4
Hey thanks both of you! HCA is 1.7. It's a Blue Nile diamond so I could ask if it's eye clean once I determine the specific diamond I want.
About Blue Nile... I know Blue Nile isn't generally recommended on here but it seems from my research that they have a little better quality settings than the other online vendors (also I like their service and have had them personally recommended to me so I would like to stick with them unless someone can talk me out of it?)
About the ideal scope.. Blue Nile doesn't offer those images as we all know.. So let's say I find a diamond that is 1.5 carat, I color, VS2 (eye clean), and scores below a 2 on the HCA tool. Is there any possibility that a diamond with those stats is gonna be a dud? I get that the ideal scope will help to select the best possible sparkle, but how much sparkle difference could there be between 2 diamonds with those same stats? Is it possible there could be a HUGE difference?
Again, thanks!!
 

Texas Leaguer

Ideal_Rock
Trade
Joined
Jul 27, 2009
Messages
3,188
ParticleMan|1456329999|3994911 said:
Hey thanks both of you! HCA is 1.7. It's a Blue Nile diamond so I could ask if it's eye clean once I determine the specific diamond I want.
About Blue Nile... I know Blue Nile isn't generally recommended on here but it seems from my research that they have a little better quality settings than the other online vendors (also I like their service and have had them personally recommended to me so I would like to stick with them unless someone can talk me out of it?)
About the ideal scope.. Blue Nile doesn't offer those images as we all know.. So let's say I find a diamond that is 1.5 carat, I color, VS2 (eye clean), and scores below a 2 on the HCA tool. Is there any possibility that a diamond with those stats is gonna be a dud? I get that the ideal scope will help to select the best possible sparkle, but how much sparkle difference could there be between 2 diamonds with those same stats? Is it possible there could be a HUGE difference?
Again, thanks!!
It's likely it will not be a dud. However, facet precision is very important for optimal light performance. HCA does not factor that in, nor does a GIA cut grade. Ideal Scope, ASET and H&A views will help you understand more about the diamond.
 

kenny

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
28,160
For rounds I'd insist on the two step process.
HCA and Idealscope image.

If a vendor does not, can not, will not provide an Idealscope image I'd buy from another vendor who does.

I have bought from and recommend Whiteflash and Goodoldgold.
I used to recommend James Allen but I heard they stopped posting IS images so they have lost my endorsement.
 

ParticleMan

Rough_Rock
Joined
Feb 24, 2016
Messages
4
Well while I'm not totally opposed to buying from Whiteflash or another site that offers images, if I can be reasonably sure that I will get a sparkly diamond from BN I would like to do so for the reasons I originally mentioned.
So, although most of the experts on here recommend using an Ideal Scope, my question is:
Are my odds really good that I can get a diamond that REALLY sparkles by just looking at the GIA cert and making sure it is below 2 HCA and then sharing the stats with the experts here for further risk reduction?
I realize I can also buy a scope but from what I've seen of it I don't think I would trust my appraisal very much as a first timer with it on this important selection!
 

diamondseeker2006

Super_Ideal_Rock
Premium
Joined
Jan 11, 2006
Messages
55,617
If you want to buy blind (no images), I would personally go by these measurements below only. And yes, VS2+.

These are measurements to help you stay in ideal cut territory with a GIA excellent cut stone.

crown angle: 34-35.0

table: 54-58

depth: 60-62.3

pavilion angle: 40.6-40.9
 

Diamond_Hawk

Brilliant_Rock
Trade
Joined
Apr 8, 2014
Messages
1,221
ParticleMan|1456346983|3995067 said:
W
Are my odds really good that I can get a diamond that REALLY sparkles by just looking at the GIA cert and making sure it is below 2 HCA and then sharing the stats with the experts here for further risk reduction?

ParticleMan,

Let me answer your question in general terms without regard to a specific diamond.

First I have a question for you, "I have a good friend who is 6 feet tall, weighs 190 lbs, blond hair, blue eyes. Will he make a good model for a fitness magazine?" Of course, no one knows. Why not? Well we only have the most basic information. It seems a good starting point, but we really must know more. The questions you are asking about the diamond are the same.

The grading report, with specific Crown and Pavilion Angles, Table, and Depth, Cut Grade and the HCA are fantastic STARTING points. They are all going to give you an idea of what to expect. Even HCA "under 2" is worthy of more investigation/information - it is an elimination tool, not a selection tool.

So, with that information you can come here and ask diamond experts (this is a made-up diamond) - "Hello there, I have a diamond that is 56 35.5 40.8 62.6 , how will it perform?"

Well, much like the 6' 190 lb. model. Maybe pretty well. But there is much, much more we need to know.

Using my example above:

56 Table - Good. That is accurate.

35.5 Crown Angle - OK - that is an average of 8 separate measurements. Could some be 34.9 and another be 36. Yes, maybe.
40.8 Pavilion Angle - Again OK - but this is also an average of 8 measurements. How big is the variance? We are not sure.

Then - we have to understand that with CA and PA the measurements are rounded. So the PA may have been rounded down from 40.9 and the CA from 35.6, further obscuring the precise angles involved.

62.6 Depth - this should be fine, but cannot be fully understood until we know the percentage of the girdle and whether or not there is some depth that also got 'rounded' when the PA and CA's were measured.

Once we know all of that we then can make guesses on the character of the diamond based on Lower Half Length, Stars and then the upper half in terms of brillianteering and even cut precision. All of these 'minute' factors in terms of rounding an possible variances will play into the light performance. And even now, with all that information - we are guessing. So, just as the model cannot be hired without specific types of images, so, too, should the diamond process go.

Light performance images using the Ideal-Scope and/or ASET (my preference) images will reveal a tremendous amount about how all the factors play together.

If possible - get the images. Otherwise your 6' 190lbs. blond/blue model may be flabby and have missing teeth.
 

kenny

Super_Ideal_Rock
Premium
Joined
Apr 30, 2005
Messages
28,160
ParticleMan|1456346983|3995067 said:
Well while I'm not totally opposed to buying from Whiteflash or another site that offers images, if I can be reasonably sure that I will get a sparkly diamond from BN I would like to do so for the reasons I originally mentioned.
So, although most of the experts on here recommend using an Ideal Scope, my question is:
Are my odds really good that I can get a diamond that REALLY sparkles by just looking at the GIA cert and making sure it is below 2 HCA and then sharing the stats with the experts here for further risk reduction?
I realize I can also buy a scope but from what I've seen of it I don't think I would trust my appraisal very much as a first timer with it on this important selection!
Here's why the HCA is not good enough.

2 of the 4 numbers you put into the HCA are averages.
Averages are dangerous.
All the numbers averaged together may happen to all be the same (a good thing) or very different (a bad thing).
With an average there's no way to know.

A round diamond actually is not round; it has 8 sides.
EACH has it's own pavilion angle.
A great Pavilion angle is 40.8 degrees.
All 8 could be 40.8 ... and that's good.
But if some were high and others were low ... even though they average out to 40.8 the diamond will have inferior light performance even with an HCA score under 2.0.
How the diamond really actually looks will be revealed by the Idealscope photograph.

Exact same problem with the crown angle(s).

This is why the the creator himself of the HCA calls it a rejection tool not an acceptance tool.

Even GIA cut grade of Excellent is not good enough.
Lots of deep dogs in there.
 

ParticleMan

Rough_Rock
Joined
Feb 24, 2016
Messages
4
Thanks everyone for the feedback. I'm going to go with Whiteflash, I had better customer service from them vs Blue Nile so far.
So let's try to boil this down. I would like your expert or prosumer opinion in regards to what my wants are:

Eye clean, H or I.

And let's do a hypothetical:

If you were a regular person (not a technical expert) and 2 people in the same room had 1.5 carat rings in those specs, and one of them had an ideal cut, and one of them had the best cut that $7500 would get from WF, how much difference in sparkle would there be? How noticeable? (If you want to expand on lighting conditions that's fine but this is just general hypothetical)

That's my real question. Although I now know a ton from months or research, I really don't know the answer to that question, which for me is the only answer I think I need at this point. In my field research, I haven't been able to compare this. I know an ideal cut sparkles more, but just how much more?

Thank you everyone!
Chris
 
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