Diamond HCA question

[titans]

How come when I put this stones in through HCA I get two different readings?
The stone is a 1.21 g si gia
http://www.gia.edu/reportcheck/index.cfm?fuseaction=home.showReportVerification&reportno=2105195497&weight=1.21
(this is the certifcate page)

The measurements are
depth 60
table 57

and if I use the
crown angle 35.5 and
pavilllion angle 41
I get a 3.7 rating

but if I use the
crown height % which is 15%
and pavillion height % which 43%
I get a 1 HCA and excellent rating

Which one should I be focusing on, and which numbers should I use.
Thanks for the help

 

[JulieN]

You should get Ideal Scope pictures.

GIA does not provide good enough numbers.

 

[titans]

Thanks,
How would I go about doing that?

 

[Regular Guy]

Date: 1/15/2009 2:10:08 PM
Author: JulieN
You should get Ideal Scope pictures.

Titans, either buy an Idealscope yourself to view, or articulate with an appraiser who uses one...see upper right under resources.

GIA does not provide good enough numbers.

Not an unreasonable statement...except that, coming from you, I wonder if it an updated or random opinion...earlier (long ago) you helped make the argument that rounding via GIA didn''t make HCA calculation suffer very much.

Meanwhile, unfortunately, the standard accepted logic is that angles DO provide a more accurate assessment than percents.

 

[titans]

Thanks for the tip regular guy. If this ring is around 3.7 on the HCA does that mean its not going to look that great? Should I be targeting something around a 2 and under?

 

[Lorelei]

Date: 1/15/2009 2:37:34 PM
Author: titans
Thanks for the tip regular guy. If this ring is around 3.7 on the HCA does that mean its not going to look that great? Should I be targeting something around a 2 and under?

Hi Titans,

In case J and Ira aren't online, the diamond you posted is what we call a steep deep, these can typically leak light so an Idealscope image is very useful to determine if there is any leakage and if so how much, and whether it is detrimental to the diamond's looks and performance. As Ira says angles are more accurate than percents but in order to get the most detailed measurements a Sarin report can be very useful if possible, but an Idealscope image would also be of great value if obtainable.

 

[titans]

Thanks again, if it wasnt for this site, i feel like i would have made an impluse bad decision already. I would rather wait and find the right stone.

 

[Lorelei]

Date: 1/15/2009 3:30:29 PM
Author: titans
Thanks again, if it wasnt for this site, i feel like i would have made an impluse bad decision already. I would rather wait and find the right stone.

We are very pleased to help you and that is the spirit - the right diamond WILL come along and you will end up with a beautiful rock!

 

[JulieN]

Date: 1/15/2009 2:24:19 PM
Author: Regular Guy

Date: 1/15/2009 2:10:08 PM

Author: JulieN

You should get Ideal Scope pictures.

Titans, either buy an Idealscope yourself to view, or articulate with an appraiser who uses one...see upper right under resources.

GIA does not provide good enough numbers.

Not an unreasonable statement...except that, coming from you, I wonder if it an updated or random opinion...earlier (long ago) you helped make the argument that rounding via GIA didn''t make HCA calculation suffer very much.


Meanwhile, unfortunately, the standard accepted logic is that angles DO provide a more accurate assessment than percents.

Lol, RG, you''re right. In the previous case, it was a comparison of the lowest and highest HCA score that a given stone''s GIA rounded angles might have gotten if GIA decided to not round. Here, it is a comparison of GIA rounded angles to GIA rounded percentages.

 

[EricaR]

Date: 1/15/2009 3:32:42 PM
Author: Lorelei

Date: 1/15/2009 3:30:29 PM
Author: titans
Thanks again, if it wasnt for this site, i feel like i would have made an impluse bad decision already. I would rather wait and find the right stone.

We are very pleased to help you and that is the spirit - the right diamond WILL come along and you will end up with a beautiful rock!

If you tell us what you are looking for we might be able to give you some suggestions.

 

[JulieN]

titans-

the depth is 62.9, and you would get an HCA score of 4 using GIA numbers.

 

[titans]

I am looking to spend between 5k to 6k on the diamond, and I am looking for an 1.15 to 1.3 ct f-g vs1 or s1, given my budget i have been mainly looking at 1.2 ct g si''s.

 

[Lorelei]

Date: 1/15/2009 3:53:50 PM
Author: titans
I am looking to spend between 5k to 6k on the diamond, and I am looking for an 1.15 to 1.3 ct f-g vs1 or s1, given my budget i have been mainly looking at 1.2 ct g si's.

What about GIA or AGS graded H colour? That would still look plenty white and help the budget if you are agreeable?

Here is a diamond you might like, I can see an inclusion to the right but it might not be visible to the naked eye, check with James Allen.

http://www.jamesallen.com/diamonds/E-SI2-Ideal-Cut-Round-Diamond-1195057.asp?b=16&a=12&c=77&cid=131

See if this one is eyeclean also.


http://www.jamesallen.com/diamonds/H-SI2-Ideal-Cut-Round-Diamond-1111991.asp?b=16&a=12&c=77&cid=131

 

[titans]

Thanks for the suggestions, Do you think an H will be noticeable non white, because I went to one place and he showed me a couple gia h''s and they where noticably not as white as F. Also arent SI2 ussually not eye clean?

 

[EricaR]

Date: 1/15/2009 4:10:09 PM
Author: titans
Thanks for the suggestions, Do you think an H will be noticeable non white, because I went to one place and he showed me a couple gia h''s and they where noticably not as white as F. Also arent SI2 ussually not eye clean?

You need to ask if the SI2 is eyeclean.

I don''t think an H would be non-white, especially if they are well cut!

 

[Lorelei]

Date: 1/15/2009 4:10:09 PM
Author: titans
Thanks for the suggestions, Do you think an H will be noticeable non white, because I went to one place and he showed me a couple gia h''s and they where noticably not as white as F. Also arent SI2 ussually not eye clean?

An H is plenty white to many but colour sensitivity varies, however a great cut will help an H colour to face up very well and it is a popular choice for some as it still looks colourless but easier on the budget. There may be a very slight difference between F and H when comparing directly, but it depends on your colour preferences as to whether an H would be a good choice for you. SI2 can be eyeclean but this clarity grade is not created equal so it is best to carefully evaluate each diamond by letting the vendor know your expectations - if you don''t want to see any visible inclusions from any angle at close scrutiny for example, make sure you let the vendor know that so you are both on the same page.

 

[titans]

Thanks alot, I will do that