Holloway Score of 5.9 on a Triple X (GIA)-Still good or not?

[flyingpig]

why do you guys think my previous ring scored much better on Holloway but paled when compared to my diamond now? Can clouds cause a diamond to not sparkle at much?

This is HCA's major flaw. Like I mentioned, HCA punishes steep and deep combos such as 36/41, which is your current stone, which can be beautiful. But HCA is unable to filter out some bad combos such as extremely steep crown (37.5) and extremely shallow pavillion (40.2). In fact, any stone with pavilion angle less than 40.5 does not even qualify for GIA X.

Just look at the graph and see how the red and yellow portion runs. It is situated low on the graph and runs diagonally, favoring shallow/shallow, shallow/deep, steep/shallow.. but not steep/deep.

I don't use HCA anymore for this and other reasons.

 

[sailorneptune]

I'm not a diamond industry guy, but my two guesses would be 1) yes, clouds can cause dullness, and 2) dirt. If you sent your old ring in for a cleaning my guess is that it would likely sparkle more.

3rd factor is that HCA is an indicator but not exact, so even good HCA stones might be duller.

It wasn't dirt, because it was brand new, fiance bought it, it ghot set, but never left the store before I changed my mind
I am so indecisive

 

[flyingpig]

Here is an example of 37/40.2, similiar to your old one.
https://www.jamesallen.com/loose-di...k-color-vs2-clarity-very-good-cut-sku-3308441
See how black contrast dominates. This contrast caused of by body shadow does not away easily even if you increased the viewing distance. also notice light leakage under the table.

Here is an 36/41, similar to current stone.
https://www.jamesallen.com/loose-di...k-color-vs2-clarity-excellent-cut-sku-3208330
Not enough contrast. also notice some yellowness and dullness under the table between the arrow shafts due to light leakage.

https://www.jamesallen.com/loose-di...k-color-vs1-clarity-excellent-cut-sku-2726688
This is what we generally recommend. good balance between brightness and contrast. crisp facets and light return under the table between the shafts. no yellowness despite being K color.

Only the last one scores HCA less than 2.0. So, using HCA would have worked if anyone was given a choice between these three.

Lastly, why PS community emphasis cut?? The most well cut stone is not significantly expensive than the other two. Also, despite being the smallest, it has got the largest spread face up.

Just an example, a well cut stone can be very expensive in certain carat/color/clarity ranges.

 

[gm89uk]

This is HCA's major flaw. Like I mentioned, HCA punishes steep and deep combos such as 36/41, which is your current stone, which can be beautiful. But HCA is unable to filter out some bad combos such as extremely steep crown (37.5) and extremely shallow pavillion (40.2). In fact, any stone with pavilion angle less than 40.5 does not even qualify for GIA X.

Just look at the graph and see how the red and yellow portion runs. It is situated low on the graph and runs diagonally, favoring shallow/shallow, shallow/deep, steep/shallow.. but not steep/deep.

I don't use HCA anymore for this and other reasons.

HCA is not wrong to not filter out 37.5/40.2 or 37.5/40.1, if paired with a small table and long LGF, maybe 85% they should be reasonable performers technically with good light return. It's just at those angles the 'minor' facets play a much bigger role as the tolerances for acceptable ranges changes. In this regard HCA doesn't account for them and rarely are they accounted for in real life, so with view to consumer use, yes not great, but for its purpose of best case scenario, can those angles achieve good light return? it fulfills.

With regards to the steep deep, light return under the table does drop off quickly, but Garry may have put the #<2 cut off too low. It might be that most people are ok with <3.5. What's the 'worst' HCA AGS 0 achieves?

 

[flyingpig]

HCA is not wrong to not filter out 37.5/40.2 or 37.5/40.1, if paired with a small table and long LGF, maybe 85% they should be reasonable performers technically with good light return. It's just at those angles the 'minor' facets play a much bigger role as the tolerances for acceptable ranges changes. In this regard HCA doesn't account for them and rarely are they accounted for in real life, so with view to consumer use, yes not great, but for its purpose of best case scenario, can those angles achieve good light return? it fulfills.

like this one??
https://www.jamesallen.com/loose-di...-color-vvs2-clarity-very-good-cut-sku-3042656

I guess you are correct in regards to light return. And HCA favours stones with strong light return or values strong light return the most. It is doing its job.
I actually like this. It appears to have decent light return and interesting facet patterns under the table Just want to see it in person, and under ASET...

 

[gm89uk]

like this one??
https://www.jamesallen.com/loose-di...-color-vvs2-clarity-very-good-cut-sku-3042656

I guess you are correct in regards to light return. And HCA favours stones with strong light return or values strong light return the most. It is doing its job.
I actually like this. It appears to have decent light return and interesting facet patterns under the table Just want to see it in person, and under ASET...

I've never had the pleasure to see a well cut 'hardcore' FIC in real life. I wonder if a trade member could comment on their performance vs tolk. I guess more fiery and a little less bright. I know Karl would have played with it plenty on diamcalc!

They sound like my dream diamond!

 

[Karl_K]

HCA is not wrong to not filter out 37.5/40.2 or 37.5/40.1, if paired with a small table and long LGF, maybe 85% they should be reasonable performers technically with good light return. It's just at those angles the 'minor' facets play a much bigger role as the tolerances for acceptable ranges changes. In this regard HCA doesn't account for them and rarely are they accounted for in real life, so with view to consumer use, yes not great, but for its purpose of best case scenario, can those angles achieve good light return? it fulfills.

With regards to the steep deep, light return under the table does drop off quickly, but Garry may have put the #<2 cut off too low. It might be that most people are ok with <3.5. What's the 'worst' HCA AGS 0 achieves?

HCA includes shallow pavilion stones for 2 reasons:
1: Garry likes them
2: they can be truly awesome in earrings and pendants where the viewing distance is greater.

There is some evidence that they are at least some what less affected by grime on the pavilion.
This makes them nice for ear rings which have gunky pavilions no matter how often you clean them in hot weather or if hair spray is used.
The evidence isn't strong enough to make that a fact however it is plausible in my opinion.

 

[Karl_K]

I've never had the pleasure to see a well cut 'hardcore' FIC in real life. I wonder if a trade member could comment on their performance vs tolk. I guess more fiery and a little less bright. I know Karl would have played with it plenty on diamcalc!

They sound like my dream diamond!

near 40 degree pavilion is going to have dark mains at full arm length.

I have seem some nice FIC diamonds in person and they are really neat diamonds.
Different personality than the near tolk super-ideals.
Tends towards showing fire more often than tolk but not as often as a step cut or oec.

 

[flyingpig]

near 40 degree pavilion is going to have dark mains at full arm length.

I have seem some nice FIC diamonds in person and they are really neat diamonds.
Different personality than the near tolk super-ideals.
Tends towards showing fire more often than tolk but not as often as a step cut or oec.

Thanks for your input.

 

[OoohShiny]

HCA includes shallow pavilion stones for 2 reasons:
1: Garry likes them
2: they can be truly awesome in earrings and pendants where the viewing distance is greater.

There is some evidence that they are at least some what less affected by grime on the pavilion.
This makes them nice for ear rings which have gunky pavilions no matter how often you clean them in hot weather or if hair spray is used.
The evidence isn't strong enough to make that a fact however it is plausible in my opinion.

IIRC @Wink conducted an experiment with shallower stones for earrings, with the result that the wearers (who weren't aware of the stones' specs) found the shallower stones to perform better as earrings, which would seem to correlate with the above.

 

[sailorneptune]

Interesting video on how both diamond that scored in the 1 range on Holloway performed. One scored slightly better on Holloway but had much less light/fire/brilliance

 

[flyingpig]

Well, this vendor does not even understand how HCA works and misinforms the viewers. 1.0 is not better than 1.4. HCA is a rejection tool. You just want the score to be less than 2.0.
0.6, 1.1, 1.8, 1.4, 1.0.. it does not matter.

Both are GIA Ex, both score less than 2.0 in HCA, both have ideal proportions. Both are beautiful, although one is arguably better than the other. HCA works as intended in this case.

 

[flyingpig]

HCA includes shallow pavilion stones for 2 reasons:
1: Garry likes them
2: they can be truly awesome in earrings and pendants where the viewing distance is greater.

And that's exactly what Garry says..
3:30

"shallow stone ... a lot of darkness ... no leakage ... not (pause) a bad stone if you viewed it from a distance... work well in earrings and pendants"