What parameters to look for in round brilliant? please help!

[anooshka]

Hello,
I'm looking to upgrade my current engagement ring and need your help. My stone is from Blue Nile, so I'll be getting a new stone with them and upgrading my setting elsewhere. I did use the HCA tool for my current stone and it scored a 1, and I love it. I wanted to know if there are ideal depth and table percentages, and crown and pavilion angles that would give me the less than 2 HCA score?
I know I can search for a range of those parameters on bluenile and I'm thinking it would be faster than just going through all the stones that fit my other criteria and calculating each one's score.

Also, my current stone is a VS1...I've seen many gorgeous SI1 and SI2 stones that are "eye clean" on here. Is it worth expanding my search to SI stones? What I mean is, is it just the "eye clean" nature of the stone that would be important? And how difficult is it to determine it being eye clean? They tell me they have notes on the stones that they can inform me with and if there are no notes, a gemologist can examine the stone and let me know. Is this suspect? or the norm?

Thank you so much, and any tips/advice you have would be really appreciated.

 

[solgen]

Re: What parameters to look for in round brilliant? please h

From what I've seen you'd want something within these ranges

depth: 60-62% (I'd say you can go to 62.3% but HCA penalizes for deeper stones)
table: 54-57%
crown angle: 34.0-35.5
pavilion angle: 40.6-41

Keep in mind that crown and pavilion angles need to be matched to some degree so you also have to look at combinations of these two angles.

There's also star facet length as well as LGF but that mostly contributes to heart&arrows patterning.

 

[AdaBeta27]

Re: What parameters to look for in round brilliant? please h

Todd Gray of NiceIce listed parameters that became "cheat sheet for sounds" Search for a thread with that title on here. Good Old Gold had an article on minor faceting in their education section on their old site. I haven't had time to look at their new one to know whether all that information is still there. Also take a look at Todd's site.

 

[anooshka]

Re: What parameters to look for in round brilliant? please h

thanks for replying!

I used the specs in this thread and found a few stones within those parameters, but when I enter the specs into the HCA calculator, it still comes up as a score of 4!!

Am I doing something wrong? Sorry if this is a silly question.

 

[ecf8503]

Re: What parameters to look for in round brilliant? please h

If BN carries AGS stones, I'd look for stones rated 000 - ideal cut (includes an ASET and has been proven to have great light return), as well as ideal polish and symmetry. Takes some of the guesswork out of things.

 

[16ocean]

Re: What parameters to look for in round brilliant? please h

thanks for replying!

I used the specs in this thread and found a few stones within those parameters, but when I enter the specs into the HCA calculator, it still comes up as a score of 4!!

Am I doing something wrong? Sorry if this is a silly question.

oh . . . that is odd . . . could you post a link to one of the diamonds you tried and I will see if we both get the same HCA score.

 

[16ocean]

Re: What parameters to look for in round brilliant? please h

I've seen many gorgeous SI1 and SI2 stones that are "eye clean" on here. Is it worth expanding my search to SI stones? What I mean is, is it just the "eye clean" nature of the stone that would be important? And how difficult is it to determine it being eye clean? They tell me they have notes on the stones that they can inform me with and if there are no notes, a gemologist can examine the stone and let me know. Is this suspect? or the norm?

eye clean . . . a big question . . . to me this means if a person can see the natural inclusions in a diamond w/ out using a loop.
It is different for every-person bz every one has not only different eye sight but a different tolerance for seeing a inclusion on their stone.
If I were to buy a SI 1 stone from blue nile I would really want a gemologist to look at it before shipping . . . I have more confidence w/ a VS-2 and if you are having to send stones back and fourth shipping adds up.
I think (and PLEASE trade/experts jump in here if this is incorrect) some inclusions can lead to decreased light performance which to me, a fan of diamonds, not an expert or professional means "less sparkly"
for example “clarity grade is based on clouds not shown" in an SI diamond is a warning for me or a black carbon mark especially in the table area.

Some SI1 stones are eye clean and some are not. You have to see it in person to know also different people have different meanings of eye clean

from the top only
from all angles

from ten inches
from six inches

"Eye clean" SI-2 are even more rare
For me:
diamond size also plays a part in eye cleanness.
For me it is easier to spot an inclusion w/ my eye in a bigger diamond. I don't know why . . .this is w/ diamonds I have seen IRL

and also for me once I know where and how to look for the inclusion I can see it very quickly . . .

 

[anooshka]

Re: What parameters to look for in round brilliant? please h

If BN carries AGS stones, I'd look for stones rated 000 - ideal cut (includes an ASET and has been proven to have great light return), as well as ideal polish and symmetry. Takes some of the guesswork out of things.

thank you. yes, I'm looking at ideal cut, excellent polish and excellent symmetry stones only. But I wanted to find something that scores well on the HCA as well, hence wondering about a range of depth/table/ and angles.