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Gorgeous stone, but HCA fail?

msop04

Super_Ideal_Rock
Premium
Joined
Dec 3, 2011
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10,051
Has anyone ever been shocked to find that a diamond you thought looked great to the eye failed miserably when HCA was calculated?

I was browsing (read: dreaming) on JA, found this stone, and thought I'd found my holy grail (I/VS2, MEDIUM FLUORO!!)... I didn't look at the angles, but really liked it in the photo and when on the carousel.

http://www.jamesallen.com/loose-dia...-i-color-vs2-clarity-excellent-cut-sku-137381

I was so shocked that the HCA was 4.6! Dang. Not that I could afford to upgrade now anyway, but... UGH!! Sad day. :blackeye:

Guess this is why the HCA is such a good tool... :|
Anyone experienced this??
 
JA video shows leakage, AGS downgrades it to a 1.
 
JulieN|1376513472|3503084 said:
JA video shows leakage, AGS downgrades it to a 1.

AHHHHH.... Julie, I just saw that! I thought it was AGS 0 (then again, I should have looked)... to try to educate myself, is the leakage shown as the dark spaces around the middle in between the arrows or how the area around the culet looks light?
 
On the sides of the bottom of the arrow shafts, you see more black than usual, which is a sign of a deep pavilion angle, the most common cause of leakage. Then you see some of the arrows going white instead of the usual black, which is a sign of leakage. The leakage itself is kind of a gray/less brilliant look under the table, between the arrow shafts.
 
Thanks, JulieN!! I have learned something today! =)
 
msop04|1376513182|3503081 said:
Has anyone ever been shocked to find that a diamond you thought looked great to the eye failed miserably when HCA was calculated?

I was browsing (read: dreaming) on JA, found this stone, and thought I'd found my holy grail (I/VS2, MEDIUM FLUORO!!)... I didn't look at the angles, but really liked it in the photo and when on the carousel.

http://www.jamesallen.com/loose-dia...-i-color-vs2-clarity-excellent-cut-sku-137381

I was so shocked that the HCA was 4.6! Dang. Not that I could afford to upgrade now anyway, but... UGH!! Sad day. :blackeye:

Guess this is why the HCA is such a good tool... :|
Anyone experienced this??

Um, yep. My new 2 carat RBC. It is AWESOME. Brought it home, plugged in the numbers- scored 3.4 on the HCA. I was upset for a few hours. But after some conversations and googling, I found that most cannot tell the difference between a Very good cut and excellent cut by looking at it with the naked eye.

I love my new diamond. And I saved a lot by going with a K, VG cut, SI2. It's COMPLETELY eye clean. And sparkly. And I love it.

It's just ME but I will never go with an HCA score over my own eyes. I don't care if it scores a .5, a 1, a 2 or a 4. In the future, if I decide to buy online, I will pay whatever it costs to see the diamond in person and I won't weed out stones that score higher than 2.

And for everyone who will argue this, don't bother. I KNOW most of you live and die by the HCA. It doesn't make a difference to me. I want to enjoy my diamond, not second guess EVERY purchase I make according to the "HCA."
 
soxfan|1376518690|3503185 said:
It's just ME but I will never go with an HCA score over my own eyes. I don't care if it scores a .5, a 1, a 2 or a 4. In the future, if I decide to buy online, I will pay whatever it costs to see the diamond in person and I won't weed out stones that score higher than 2.

And for everyone who will argue this, don't bother. I KNOW most of you live and die by the HCA. It doesn't make a difference to me. I want to enjoy my diamond, not second guess EVERY purchase I make according to the "HCA."

Great attitude, sox!! My stone scored a 2.6, but it knocks my eyeballs out and I lurv it! :praise:
 
msop04|1376519196|3503195 said:
soxfan|1376518690|3503185 said:
It's just ME but I will never go with an HCA score over my own eyes. I don't care if it scores a .5, a 1, a 2 or a 4. In the future, if I decide to buy online, I will pay whatever it costs to see the diamond in person and I won't weed out stones that score higher than 2.

And for everyone who will argue this, don't bother. I KNOW most of you live and die by the HCA. It doesn't make a difference to me. I want to enjoy my diamond, not second guess EVERY purchase I make according to the "HCA."

Great attitude, sox!! My stone scored a 2.6, but it knocks my eyeballs out and I lurv it! :praise:

Right? I chose my stone (and had NO prior knowledge) over an F or G EX cut. I just fell in love with it....I will NEVER rule out a GIA VG cut in the future.

Although..... I have my sights set on an AVR or Canera cushion for my next upgrade :love: I will have to read up on how those are graded.... :lol:
 
I prefer ideal cut,personally, but that doesn't mean that there aren't other pretty diamonds that are not. My original diamond is probably no better than good, and it is a pretty diamond. But when I went to look for an upgrade diamond, my choice was to go for the very best cut and not make size my #1 factor. And I think it has paid off for me, because I have now sold two excellent/ideal cut stones without losing money which allowed me to buy #3!

I never use HCA on AGS graded stones since they grade cut. It is really for GIA stones since GIA Excellent is such a broad category.
 
diamondseeker2006|1376520064|3503214 said:
I prefer ideal cut,personally, but that doesn't mean that there aren't other pretty diamonds that are not. My original diamond is probably no better than good, and it is a pretty diamond. But when I went to look for an upgrade diamond, my choice was to go for the very best cut and not make size my #1 factor. And I think it has paid off for me, because I have now sold two excellent/ideal cut stones without losing money which allowed me to buy #3!

I never use HCA on AGS graded stones since they grade cut. It is really for GIA stones since GIA Excellent is such a broad category.

I never knew this about the HCA!! Thanks for the info -- I'll definitely keep that in mind when, errr, umm... IF I upgrade. :Up_to_something:

My eyes might still talk me into buying that stone if I liked the way it looked in person... leakage and all! :lol:
 
msop04|1376521927|3503245 said:
diamondseeker2006|1376520064|3503214 said:
I prefer ideal cut,personally, but that doesn't mean that there aren't other pretty diamonds that are not. My original diamond is probably no better than good, and it is a pretty diamond. But when I went to look for an upgrade diamond, my choice was to go for the very best cut and not make size my #1 factor. And I think it has paid off for me, because I have now sold two excellent/ideal cut stones without losing money which allowed me to buy #3!

I never use HCA on AGS graded stones since they grade cut. It is really for GIA stones since GIA Excellent is such a broad category.

I never knew this about the HCA!! Thanks for the info -- I'll definitely keep that in mind when, errr, umm... IF I upgrade. :Up_to_something:

My eyes might still talk me into buying that stone if I liked the way it looked in person... leakage and all! :lol:

This. When I plugged in the numbers of my stone in AGS, I got "ideal" cut. We are also plugging in the same general numbers on the HCA, right?
Exactly. You have to SEE it.

The eyes have it....
 
Yes, for sure. My mom's stone scored around a 4.5 on HCA, and I swear that rock sparkles more than mine, which was just under 2.0 on HCA. Well, who knows. Maybe my eyes are warped and no one else will agree when they look at it. But if I'm buying, it's my eyes that will be glued to it all the time. I guess that is why people say you have to LOOK at it before committing. Is it like dating? Some people look perfect on paper, but then IRL...what???!!!!
 
LLJsmom|1376524588|3503297 said:
Yes, for sure. My mom's stone scored around a 4.5 on HCA, and I swear that rock sparkles more than mine, which was just under 2.0 on HCA. Well, who knows. Maybe my eyes are warped and no one else will agree when they look at it. But if I'm buying, it's my eyes that will be glued to it all the time. I guess that is why people say you have to LOOK at it before committing. Is it like dating? Some people look perfect on paper, but then IRL...what???!!!!

I wish this was facebook so I could hit "like." :lol:
 
It's difficult and x pensive to find a superideal cut diamond once you hit the 2ct mark. To me, it's not worth paying the premium, and I'd easily settle for a VG cut if I liked the look of the diamond and the price fit my budget. Before the HCA and Pricescope and all of it's information, people just bought what they liked and were happy with it. :bigsmile:
 
Interesting thread.
Every diamond "leaks" light. That aspect , in and of itself, does not mean a diamond is badly cut.
I'm sure JulieN is seeing some leakage- but I'd add that the manner in which the diamond is shown has pluses and minuses in terms of representing how it looks in real life.
This is true of every method of photography/Video of a diamond.
So, the leakage present might not necessarily be a negative when looking at the stone in person.
The HCA is a very good predictor of a particular look- but what it can not predict is what your eyes will prefer.
When I chose a stone for my wife a few years back it was done solely on the look.
It was a GIA EX cut grade- 60/60- that scored 5.6 on HCA.
And it was an amazing stone....since traded up.
DW has the ultimate trade up policy :twirl:

Anyway, my point is that using HCa - or AGS light performance measurements gives valuable information- but using this as a benchmark will overlook other, even more vital information IMO
 
I LOVE this thread. Love it.
 
I think for a lot of ppl it is the issue with mind clean as well. I personally don't want to pay for a lesser performing diamond. They are already expensive enough as it is. And I will say after the LAS GTG I was super surprised how much cut made a difference with MRBs (which are obviously not my cuppa of tea but to each their own). HCA is great as a weeding tool but it is not the end all be all for some. If you are looking for diamonds at a value they will probably end up being over 2 for a reason. But who cares if you love it. However most ppl who come to PS, do care, and want the best performing diamond. Especially the guys who are proposing and *cough cough* dont understand yet the importance of an upgrade. So to sum up I don't think the tool should be downplayed when you are looking for the best diamond you can get.
 
Personally, I don't believe the word performance is applicable in this situation.
I know it's used here a lot- but I think that it's misleading
We're talking about preference. Mind clean is a more applicable term for this IMO
Does a Ribeye "perform" better than a Filet Mignon?
Although it costs more to buy a "super ideal" HCA has no bearing whatsoever on prices of regular GIA EX cut grade stones
And even if we are comparing to what I'm calling super ideal cuts, a fair percentage of observers will prefer the look ( performance ) of a stone that scores lower ( higher numerically) on HCA
This will be due to aspects like LGF length and spread-'also scintillation versus contrast.
By all means go for what pleases your eye and pocketbook
But many GIA EX or VG cut grade stones scoring over 3 or 4 or even 5, can be just as attractive as a stone scoring less than two on HCA
 
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