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Need help! GIA XXX with HCA of 3.7

S

scarletbird

Rough_Rock
Joined
Jun 4, 2013
Messages
13
H:
I am a total newbie with regard to diamonds. I have been following this forum & pricescope to educate myself:) This is like a treasure trove 4 developing knowledge on diamonds!
Need the expert's help here to help me with my purchase - Trying 2 get a round brilliant F Si2 dia ( 3 carat) for my fiance. Found a GIA XXX with Strong Blu FL. The online vendor assures me its eye clean and has Hearts n arrows and is not milky. However. when I plug numbers into the HCA tool I get a 3.7.They cannot share aset or ideal scope pictures. I am concerned about light leakage - should I be with a GIA XXX? Pls advise.
Your assistance is greatly appreciated:)
 
There are better and worse GIA Triple Exs, the HCA tries to weed out the bad ones. Just because the stone has H&A doesn't mean it's a top performer. It even depends on how strict the vendor's parameters for H&A are.

Can you post all the information, like pavilion/crown angle, or post the GIA cert?

Edit: Sorry, just read that they cannot provide IS/ASET images, which puts you at a disadvantage. Did they say at what distance the SI2 is eye clean to? Vendors have different standards for eye clean, most are at 10 inches from the top view, while you may interpret eye clean as 6 inches from all sides
 
Hi:

thx 4 the superfast response. They will not provide me with any other Aset or idealscope images.
Your advice is gr8ly appreciated.
here's the GIA report :
GIA REPORT NUMBER
1149804851
DATE OF ISSUE
3/28/2013

DIAMOND GRADING REPORT
ROUND BRILLIANT

Measurements 9.60 - 9.65 x 6.00 mm
Carat Weight 3.43 carat
Color Grade F
Clarity Grade SI2
Cut Grade Excellent
PROPORTIONS

Depth 62.4 %
Table 57 %
Crown Angle 35.0°
Crown Height 15.0%
Pavilion Angle 41.2°
Pavilion Depth 43.5%
Star Length 50%
Lower Half 80%
Girdle Medium to Slightly Thick, Faceted, 4.0%
Culet None
FINISH

Polish Excellent
Symmetry Excellent
FLUORESCENCE

Fluorescence Strong Blue
CLARITY CHARACTERISTICS

Clarity Characteristics Crystal, Cloud, Needle
 
Do you have any pictures? The pavilion angle is high but you really need an idealscope to see what's going on. Post a pic if you
have any.
 
Unfortunately Vendor does not provide any other pics ( idelascope etc).
 
I would not buy it because HCA score is over 2.0.
GIA Excellent cut has a wide range and includes some that are not as well cut as others.
Why buy that stone when there are better-cut ones out there?
Let someone else buy it who doesn't know any better.
You know better now.

I'd find another stone, preferably from another vendor that provides Idealscope pics.
I'd try Goodoldgold, Whiteflash, Jamesallen, Briangavindiamonds.
 
I agree about opening the search to other vendors who provide the images you need to make an informed purchase. You're about to spend quite a large amount of money, wouldn't you want to know exactly what you're buying, and want to know that you got the very best for your money?

If you're open to it, post your budget, and other preferences and we can help find something.
 
Hi all:

thx 4 the sound advice and steering me away from making a bad choice- i have now decided against this stone. However totally confused. my budget is ~35 to 40k max. She wants a large stone - tjats y i was looking at 3 carat - would like in the colorless but lower clarity ( however she wants absolutely eye clean) with hearts and arrows.
Thx much!
 
Delete.
 
Your requirements are pretty tight (colorless, eyeclean SI2 under 40K) so don't get too hung up over things like HCA score.

Does vendor provide hearts pictures to confirm H&A?
 
JulieN|1376803792|3505151 said:
Your requirements are pretty tight (colorless, eyeclean SI2 under 40K) so don't get too hung up over things like HCA score.
Click to expand...

HUH?
Please BE 'hung up' ( :roll: ) over the HCA score.
That or, raise your budget or look for a smaller diamond.

Cut is everything.
Cut is more important than color or clarity for a diamond to give off that spectacular light show.

HCA is step 1 to finding a well-cut round.
Step 2 is comparing an Idealscope image to this chart.



For those of us without psychic powers, this bullet-proof 2-step process ensures a well-cut round.
It may reject a few rounds that experts with years of experience may know are also good.
So what?
You and I are not experts with years of experience.

idealscope_ref_26.png
 
1) stereo vision. HCA of 2-3 can have no visible leakage.

2) GIA rounding is too imprecise to say 3.7 is not ok, but 3 is ok.

3) OP should probably choose a vendor who can provide quality pictures or a free shipping both ways policy.
 
JulieN|1376805142|3505155 said:
1) stereo vision. HCA of 2-3 can have no visible leakage.

2) GIA rounding is too imprecise to say 3.7 is not ok, but 3 is ok.
Click to expand...


3 is okay?

Okay?
I don't want okay.
I'd want the best light performance my $40K (or any budget) can buy.

But sure, people vary.
Some don't care about light performance.
If so ignore HCA and IS.
 
Hi All:

Thx 4 the healthy dialog- this is y this forum is so gr8:)
I am going with what Kenny says - I absolutely DO NOT want to settle for a OK diamond. Its just my ignorance. Thought I cud not go rong with GIA XXX, and I absolutely want to pick a dia with the best light performance and (hearts n arrows which she loves). Also thought my requirements were stringent ..... So much for my ignorance.. LOL:)
I am thinking I need to select a smaller diamond....any advice is gr8ly appreciated. Also. will independent appraisers look at light performance (i.e IS images) if the the vendor does not provide these?
Thx a million:)
 
Hi All:

Thx 4 the healthy dialog- this is y this forum is so gr8:)
I am going with what Kenny says - I absolutely DO NOT want to settle for a OK diamond. Its just my ignorance. Thought I cud not go rong with GIA XXX, and I absolutely want to pick a dia with the best light performance and (hearts n arrows which she loves). Also thought my requirements were stringent ..... So much for my ignorance.. LOL:)
I am thinking I need to select a smaller diamond....any advice is gr8ly appreciated. Also. will independent appraisers look at light performance (i.e IS images) if the the vendor does not provide these?
Thx a million:)
 
thx again 4 all ur input. One question, can a newbie like me get access 2 this simulation tool - this way I can model the light leakage etc for potential diamonds esp as the vendor does not share? pls advise. thx
 
scarletbird|1376840784|3505338 said:
thx again 4 all ur input. One question, can a newbie like me get access 2 this simulation tool - this way I can model the light leakage etc for potential diamonds esp as the vendor does not share? pls advise. thx
Click to expand...

You can buy the scope- but you need the diamond to use it with....
 
soxfan|1376834960|3505273 said:
My "very good cut" scored a 3.4 on the HCA. It is a beautiful diamond. Here is a thread here where John Pollard actually plugged in the numbers and did some images on it.

[URL='https://www.pricescope.com/community/threads/gia-vs-ags-cut-grading.192169/']https://www.pricescope.com/community/threads/gia-vs-ags-cut-grading.192169/[/URL]

Sometimes some really nice diamonds can fall through the cracks in the HCA tool.

Just my opinion....
Click to expand...

Good point.
As I mentioned some good ones fail the two-step process.
The problem is identifying them.

I fear some noobs will read that a 3.4 was okay per an expert so they'll reason that all 3.4s are as good as a 1.0, which is a logic-fail.

Unless you are an expert or have psychic powers or have John Pollard or Paul Slegers or KarlK by your side ... reject diamonds that score over 2.0, and get IS pic on those that score under 2.0.

That is an easy no-risk process any noob can do.
Departing from the process is a risk.
 
The chart posted above has no place in a discussion about HCA stores, or diamonds with a GIA EX cut grade. You're not going to see stones graded EX Cut grade by GIA that look anything like the stones on the right side of the chart.
It's simply inaccurate- and misleading to say a stone scoring 3.7 is worse than a stone scoring 1 when it comes to cut.
If someone has looked at different stones and knows what the HCA looks for, then it can be a useful tool.
BUT, some people will pick a stone that scores 3.7 over one that scores 1 based on aspects which HCA can not distinguish.
Things like LGF.
scarletbird, what this means is how wide the shafts are when you see the arrows pattern in the diamond.The higher the LGF%, the more narrow the shafts will be.
Narrower shafts will not produce a distinct H&A pattern.
Some people prefer a distinct H&A pattern, others a more disorganized type of sparkle.

Some people will prefer more contrast ( rewarded in HCA) while others prefer more scintillation( dinged by HCA)
GIA does not punish stones for things HCA does- yet we're talking about preference.
For this reason, GIA EX cut grade means more than HCA to noobies who are actually looking at diamonds- period.
scarletbird - if you can get to places that carry diamonds and have a look for yourself, it will be helpful.
Its a major league purchase and worth your time.
 
Hi All:
Thx much for the advice - here is my problem.
I do not want to pay the premium in a bricks and mortar place so was settling in on online purchase. I would really like to follow the 2 step process outlined by Kenny. However, am stuck as I cant get the ASET r IS images from the vendor. Given the novice I am want 2 play it safe -is there any tool available besides the HCA that i can plug the dia characteristics to light performance ( like the images shared earlier). This way I can narrow down my selection and finally make a choice. Whew! did not realize that this is so complicated.
Thx all 4 ur patience with me and ur guidance.
 
Light performance is not a static thing.
As I mentioned- the image posted by Kenny is not really applicable with a GIA EX cut grade.
It's a preference as to which type of look you love best.
That's why I suggest that you look at stones in person at a B&M.
After you've looked at stones yourself, you'll be in a better position to put context to the advice given here.
Where to purchase, of course that's up to you.
There are also vendors online that will provide more info.
They may have higher prices- but sometimes consumer are willing to pay more to alleviate the doubt you're facing.
 
kenny|1376847426|3505413 said:
soxfan|1376834960|3505273 said:
My "very good cut" scored a 3.4 on the HCA. It is a beautiful diamond. Here is a thread here where John Pollard actually plugged in the numbers and did some images on it.

[URL='https://www.pricescope.com/community/threads/gia-vs-ags-cut-grading.192169/']https://www.pricescope.com/community/threads/gia-vs-ags-cut-grading.192169/[/URL]

Sometimes some really nice diamonds can fall through the cracks in the HCA tool.

Just my opinion....
Click to expand...

Good point.
As I mentioned some good ones fail the two-step process.
The problem is identifying them.

I fear some noobs will read that a 3.4 was okay per an expert so they'll reason that all 3.4s are as good as a 1.0, which is a logic-fail.

Unless you are an expert or have psychic powers or have John Pollard or Paul Slegers or KarlK by your side ... reject diamonds that score over 2.0, and get IS pic on those that score under 2.0.

That is an easy no-risk process any noob can do.
Departing from the process is a risk.
Click to expand...

Yes, you are right. I didn't mean to imply that all of the ones that score over 2 are great. And I get what you are saying, as most order online based on the number/idealscope/Aset images WITHOUT seeing the stone in person. I just meant if you could see it in person, and THEN weigh all the factors..

WHICH PS-recommended vendors actually mail you diamonds to let you choose? Is it more than one? Or do most just do the scope, etc?
 
I agree with David (RockDiamond) and JulieN on this. The HCA prefers shallower stones and penalizes stones with steeper crowns paired with steeper pavilion angles. Also, I believe HCA is much more accurate with AGS graded stones than with GIA graded stones because of the rounding that is mentioned. Finally, light return as measured by an Idealscope (IS) viewer, tells only part of the story. Brilliance, fire, and scintillation are not measured by the IS. Brilliance, fire, and scintillation are, I'd argue, the appeal of a diamond. There are diamonds cut to perfect proportions under AGS and GIA that suffer in one or more of those aspects. I have seen them. So, one key thing to remember is that it's not just the angles per se, it's how the angles work together that create a beautiful diamond. Another key thing to remember is that not everyone's eyes perceive "beauty" in the same way. The favored PS diamond is an ideal cut with a smaller table -- 53 or 54% -- and a high crown and shorter lower girdle facets -- 75%. I find such diamonds dark (to my eyes) with too much contrast, excellent fire, but not enough brillance or sparkle. Additionally, not all diamond crystal is created equal. There are some diamonds that appear to have a brown or yellow or grey or green "cast" to the crystal. This cast has nothing to do with the color grading (D, E, F, etc.) and is not noted on the grading report unless it is fairly significant. A diamond I once owned had an almost imperceptible grey-ish cast and I absolutely hated it. This is why you have to see the diamond in person -- especially such a large diamond -- before you buy it, and why you need to buy a diamond from a company with a good return policy, whether or not it is an online vendor or a bricks and mortar store. You cannot buy diamonds by the numbers!

On another note, there were some fascinating old threads discussing the merits of diamonds cut with 35 crowns and 41 pavilions (with 62% depth and 56% tables, if I remember right). I'll see if I can dig them up.
 
soxfan|1376858340|3505504 said:
kenny|1376847426|3505413 said:
soxfan|1376834960|3505273 said:
My "very good cut" scored a 3.4 on the HCA. It is a beautiful diamond. Here is a thread here where John Pollard actually plugged in the numbers and did some images on it.

[URL='https://www.pricescope.com/community/threads/gia-vs-ags-cut-grading.192169/']https://www.pricescope.com/community/threads/gia-vs-ags-cut-grading.192169/[/URL]

Sometimes some really nice diamonds can fall through the cracks in the HCA tool.

Just my opinion....
Click to expand...

Good point.
As I mentioned some good ones fail the two-step process.
The problem is identifying them.

I fear some noobs will read that a 3.4 was okay per an expert so they'll reason that all 3.4s are as good as a 1.0, which is a logic-fail.

Unless you are an expert or have psychic powers or have John Pollard or Paul Slegers or KarlK by your side ... reject diamonds that score over 2.0, and get IS pic on those that score under 2.0.

That is an easy no-risk process any noob can do.
Departing from the process is a risk.
Click to expand...

Yes, you are right. I didn't mean to imply that all of the ones that score over 2 are great. And I get what you are saying, as most order online based on the number/idealscope/Aset images WITHOUT seeing the stone in person. I just meant if you could see it in person, and THEN weigh all the factors..

WHICH PS-recommended vendors actually mail you diamonds to let you choose? Is it more than one? Or do most just do the scope, etc?
Click to expand...

I agree with the underlined, but want to add that any consumer can have John Pollard or Paul Slegers by his/her side if he/she buys a Crafted by Infinity branded diamond ;))
 
OP, is there a reason why you're sticking with your vendor, despite them not being able to provide those images? Would you be open to us giving you suggestions from other vendors? IMO it'll be very hard to find something that meets all of your criteria, especially the size for a colorless range for your budget, but it'll be one of the best performing out there, something you can't be sure of with this stone.

I hope you don't leave with the thought that you shouldn't your stone online because it's too risky, especially since it's quite a large stone. There are ways of mitigating the risks... you can use the HCA, get IS/ASET images, buy a branded diamond like WF's ACA, BGD's signature, etc.
 
I have had Good Old Gold and WhiteFlash send me diamonds to look at from their in-stock inventory. But I don't really find that necessary for an ideal cut round as long as I can see photos and idealscope. If top cut and absolutely eyeclean are important to her, you simply are going to be in trouble dealing with vendors who do not supply more information. Even some SI1 stones are risky at this size.

Here is a beautiful 3 ct H SI1 at $45k:

http://www.goodoldgold.com/diamond/11173/

more...

http://www.goodoldgold.com/diamond/11171/ ($46, 400)

http://www.goodoldgold.com/diamond/9472/ ($39k, if totally eyeclean)

http://www.briangavindiamonds.com/diamonds/diamond-details/2.835-h-si1-round-diamond-ags-104065335001

And I don't see any at WF at the moment.
 
Rockdiamond|1376848912|3505429 said:
The chart posted above has no place in a discussion about HCA stores, or diamonds with a GIA EX cut grade. You're not going to see stones graded EX Cut grade by GIA that look anything like the stones on the right side of the chart.
It's simply inaccurate- and misleading to say a stone scoring 3.7 is worse than a stone scoring 1 when it comes to cut.
If someone has looked at different stones and knows what the HCA looks for, then it can be a useful tool.
BUT, some people will pick a stone that scores 3.7 over one that scores 1 based on aspects which HCA can not distinguish.
Things like LGF.
scarletbird, what this means is how wide the shafts are when you see the arrows pattern in the diamond.The higher the LGF%, the more narrow the shafts will be.
Narrower shafts will not produce a distinct H&A pattern.
Some people prefer a distinct H&A pattern, others a more disorganized type of sparkle.

Some people will prefer more contrast ( rewarded in HCA) while others prefer more scintillation( dinged by HCA)
GIA does not punish stones for things HCA does- yet we're talking about preference.
For this reason, GIA EX cut grade means more than HCA to noobies who are actually looking at diamonds- period.
scarletbird - if you can get to places that carry diamonds and have a look for yourself, it will be helpful.
Its a major league purchase and worth your time.
Click to expand...


While I agree that this is perhaps good advice for some people, the OP has already stated that his girlfriends values the optics provided by a hearts and arrows stone, so I'm not sure that it's the best advice in THIS case. If OP values HA then I would suggest working with a vendor that specializes in HA cuts and can help him find a stone that will both perform well and exhibit the optical symmetry his girlfriend prefers.
 
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