HCA tool below 1

[Garry H (Cut Nut)]

Which would be better for a ring... an hca score under 1 that signals big or bigger ? Not sure what the distinction is. Just looked up a super ideal out of curiosity. It came out .90 bigger. Thanks.

I think we can over think this stuff Mlh.
But Johnbt's post says a lot. I do not know of a condition where people get more short sighted.

 

[OoohShiny]

The market pricing is great for the informed, but first times have no idea that a radiant for example can spread 5% bigger than a round or 40% smaller.
As for art - Sergey and the Cut Group have an unrequited plan to hold a diamond cut competition. We had hoped a decade ago to get support from the Indian gem and jewellery association but the leadership changed.
India would be the perfect place to start something like this as there are so many engineers etc involved in planning the cutting of each piece of rough diamond. They could moonlight or work from within their company.

Ooooh, that could be cool!

 

[Garry H (Cut Nut)]

As I understand it, all other things being equal, Bigger in a sub 1 would tend to be shallower than Big and therefore may be darker close up. However, as is often said on the PS threads, HCA is a rejection tool and you can’t say which is the better diamond just from two low scores.

I compared a 0.5 score side-by-side with a 1.0 score......the arrows were *maybe* marginally darker close up in the 0.5, but I do mean maybe and marginal!

And the lower girdle length becomes more critical too. Shallow stones with short lower girdles and fat stars are bad.
And for FIC's with very steep crown angles the lower girdles should also get much longer.
No one ever seems to notice that.
So there is a mid point that is fatter for Tolkowsky that can get longer depending on the pavilion angle getting shallower.

 

[Mlh]

I think we can over think this stuff Mlh.
But Johnbt's post says a lot. I do not know of a condition where people get more short sighted.

Thank you Garry!! Yes, a lot of over thinking!

 

[Mlh]

As I understand it, all other things being equal, Bigger in a sub 1 would tend to be shallower than Big and therefore may be darker close up. However, as is often said on the PS threads, HCA is a rejection tool and you can’t say which is the better diamond just from two low scores.

I compared a 0.5 score side-by-side with a 1.0 score......the arrows were *maybe* marginally darker close up in the 0.5, but I do mean maybe and marginal!

Thanks @mission1 !! Very interesting to know. I checked a couple of super ideals under 1ct and they came up as bigger.

 

[AdamG]

@Garry H (Cut Nut) I find your tool very fascinating and appreciate your insights into the cuts of diamonds. Based on your experience, which of the below do you think would make for the best engagement ring? (Note it will be a simple 4-prong setting on a knife-edge platinum band with no halo or smaller crystals. The lady is a ring size 6.5.)

2.01 ct I SI1 (HCA score of 0.7 - big). GIA cert with dimensions. See attachment for photo of ASET.
2.02 ct I SI1 (HCA score of 1.6 - average). GIA cert with dimensions.
2.23 ct G SI1 (HCA score of 1.3 - average). GIA cert with dimensions.

I've seen the 2.01 ct and 2.23 ct in person but it's not possible to see them next to each other so it's difficult to tell which is better (both are eye clean). I have only seen the 2.02 ct online. I only have an ASET for the 2.01 ct at this time. I'm having a tough time coming to a decision and would very much value your opinion/advice. I understand you also cannot see the diamonds at all but am looking for your opinion based on the dimensions and info provided.

Best,
Adam

 

[OoohShiny]

@Garry H (Cut Nut) I find your tool very fascinating and appreciate your insights into the cuts of diamonds. Based on your experience, which of the below do you think would make for the best engagement ring? (Note it will be a simple 4-prong setting on a knife-edge platinum band with no halo or smaller crystals. The lady is a ring size 6.5.)

2.01 ct I SI1 (HCA score of 0.7 - big). GIA cert with dimensions. See attachment for photo of ASET.
2.02 ct I SI1 (HCA score of 1.6 - average). GIA cert with dimensions.
2.23 ct G SI1 (HCA score of 1.3 - average). GIA cert with dimensions.

I've seen the 2.01 ct and 2.23 ct in person but it's not possible to see them next to each other so it's difficult to tell which is better (both are eye clean). I have only seen the 2.02 ct online. I only have an ASET for the 2.01 ct at this time. I'm having a tough time coming to a decision and would very much value your opinion/advice. I understand you also cannot see the diamonds at all but am looking for your opinion based on the dimensions and info provided.

Best,
Adam

You could start a new thread and get other members' input as well

 

[AV_]

As for art - Sergey and the Cut Group have an unrequited plan to hold a diamond cut competition.

I am not entirely certain art works that way [engineering, perhaps, since it knows where it is going, but I hardly know anything about that]

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