ACA diamonds - splitting hairs!!

[Texas Leaguer]

Is it, then, that some degree of leakage is inherent in the various cuts, and the idea is to reduce it as much as possible while making the leakage that remains work toward the overall effect?

This is a pretty good way of saying it.

As @Karl_K and others have mentioned it is technically possible to remove the remaining 5% or so of leakage in the standard round brilliant by tweaking the pointing direction of the girdle facets. Eightstar popularized this style, and others began offering versions of it to maximize volume of light return. Interestingly, over time it became clear that there was no consensus that this 'flavor' was superior in terms of aesthetics.

It turns out that certain leakage in the right amount and distribution contributes a subtle type of contrast to a diamond that enhances scintillation. This same effect (contrast leakage) is undoubtedly part of the reason why certain fancy shapes such as 'crushed ice' cushions have very pleasing aesthetics to many people despite ASETs that show a lot of interspersed white.

Contrast is created mainly by the on/off nature of an illuminated facet next to an obstructed facet (or virtual facet), but a bit of contrast is also created by an illuminated facet next to a "window" facet, though much more subtle.

 

[daydreamer24]

@daydreamer24 You've entered the analysis paralysis zone. Watch the videos and go with your gut feelings. You wont be wrong.
Is this stone for you or your GF? If I were you, I* would go with the H.

It’s for my girlfriend. For some reason, the I diamond does speak to me more. The videos show very distinctly the 8 arrows and i think maybe I’m slightly put off the inclusion jsut under the table, despite WF confirming it’s completely eye clean. I guess I’m struggling with the mind clean aspect.

Thanks for everyone’s help on this. I really appreciate it. I will need to analyse a bit more and make my decision soon!

 

[Venzen007]

Don't set yourself up with a false dichotomy; there are more choices than just those two! Maybe you're still analyzing because you just don't love either. Just a thought. Disregard if you feel you've really played the field to narrow to these two.

 

[kmoro]

Just gonna say that color is more noticeable than clarity when talking about two eye-clean diamonds

 

[atp223]

I don't know what size these are, but I have a 2.9 ct AGS I (from Brian Gavin), and am super happy with it. It is set in yellow gold, but I don't notice tint on top at all. And it is a 6 prong setting, so you don't see a ton of the diamond from the sides.

 

[Yang Kin]

Thanks for your input. Can you tell the poster what star length range you prefer and why? She is trying to learn and analyze all these numbers. Thanks!

I have a 48% star length ACA, it exhibits more brightness than fire IMO. I can't say for sure all 48% star length diamonds will be like that, but gut feeling tells me a 50% and above star length can perform better. Again, gut feeling, so take it with a pinch of salt.

 

[MissGotRocks]

I have a 48% star length ACA, it exhibits more brightness than fire IMO. I can't say for sure all 48% star length diamonds will be like that, but gut feeling tells me a 50% and above star length can perform better. Again, gut feeling, so take it with a pinch of salt.

I understand. I once read that the star length of course has a range but it was the least likely to be problematic. Like you, I'm not sure if that is correct either. My ACA has a 51 so not sure how that compares to yours - I think though that the crown/pavilion angles might make more of a difference.

Thanks for coming back to clarify!

 

[Yang Kin]

I understand. I once read that the star length of course has a range but it was the least likely to be problematic. Like you, I'm not sure if that is correct either. My ACA has a 51 so not sure how that compares to yours - I think though that the crown/pavilion angles might make more of a difference.

Thanks for coming back to clarify!

Yup. Totally agree that crown and pavilion angles play a more vital role. Always excited to see a crown that goes nearer to 34 degree and the pavilion that goes nearer to a 40.9 degree. Just feels good to have a proper inverse relationship between these two. And of course, this is a matter of personal preference.

I also like smaller table and taller crown if there is an option to choose.

Oh I have another ACA with 53% star length. Looks sparkly and fiery. Somewhat suit my taste better.

 

[MissGotRocks]

Yup. Totally agree that crown and pavilion angles play a more vital role. Always excited to see a crown that goes nearer to 34 degree and the pavilion that goes nearer to a 40.9 degree. Just feels good to have a proper inverse relationship between these two. And of course, this is a matter of personal preference.

I also like smaller table and taller crown if there is an option to choose.

Oh I have another ACA with 53% star length. Looks sparkly and fiery. Somewhat suit my taste better.

So interesting! I had a 34/40.9/57 table stone (non ACA) and now I have a 34.8/40.8/56 table stone (ACA).

There is definitely a difference between the flavors.

Interested to know which is your favorite - the 34/40.9 or the small table, high crown?

 

[Yang Kin]

So interesting! I had a 34/40.9/57 table stone (non ACA) and now I have a 34.8/40.8/56 table stone (ACA).

There is definitely a difference between the flavors.

Interested to know which is your favorite - the 34/40.9 or the small table, high crown?

This is an interesting question. Before that, let me highlight that I only have smaller carat weight stones to compare, but since they are both approximately the same size, at 0.2ct and 0.211ct respectively, I think it is okay to compare them.

The 0.2ct I have has a 59% table together with a 60.4% depth. Crown height is 14%. CA is 34 degree and PA is 48 degree, and GIA graded. For the 0.211ct I have, it has a 55.8% table together with a 61.8% depth. Crown height is 15.4%. CA is 34.8 degree and PA is 40.8 degree, and AGS graded.

Now, the 0.2ct is glowing with brightness and returning a decent amount of fire. It feels very sunshine with all the brightness around. When compare this to the 0.211ct, the 0.211ct is very bright too, but it will go slightly dimmer to give way for more obvious fire. Both are lovely diamonds, but I will pick the 0.211ct as I prefer fire over brightness... Most of the time.

A few other things:
Do note that my 0.2ct's table is wider than your diamond's 57% table.
The cut quality on the 0.2ct GIA diamond is pretty decent. At least near Hearts & Arrows.

On a side note, I should say that I should cap my crown angle at 34.3 degree, when moving towards the shallower side. So, if I see something like 34.4 CA and 40.8 PA, I am a happy man.

 

[MissGotRocks]

This is an interesting question. Before that, let me highlight that I only have smaller carat weight stones to compare, but since they are both approximately the same size, at 0.2ct and 0.211ct respectively, I think it is okay to compare them.

The 0.2ct I have has a 59% table together with a 60.4% depth. Crown height is 14%. CA is 34 degree and PA is 48 degree, and GIA graded. For the 0.211ct I have, it has a 55.8% table together with a 61.8% depth. Crown height is 15.4%. CA is 34.8 degree and PA is 40.8 degree, and AGS graded.

Now, the 0.2ct is glowing with brightness and returning a decent amount of fire. It feels very sunshine with all the brightness around. When compare this to the 0.211ct, the 0.211ct is very bright too, but it will go slightly dimmer to give way for more obvious fire. Both are lovely diamonds, but I will pick the 0.211ct as I prefer fire over brightness... Most of the time.

A few other things:
Do note that my 0.2ct's table is wider than your diamond's 57% table.
The cut quality on the 0.2ct GIA diamond is pretty decent. At least near Hearts & Arrows.

On a side note, I should say that I should cap my crown angle at 34.3 degree, when moving towards the shallower side. So, if I see something like 34.4 CA and 40.8 PA, I am a happy man.

Thank you for the review. I am sure they are both beautiful diamonds. Though there are not nearly as many men here as there are women, it seems to me that all of the men prefer the fire over brightness. Just my observation but very interesting to me. Thanks again for taking the time to respond to my questions!