questions from a newbie....

[newbie12345]

Been searching for a .9 ct VS2 diamond for about 6 months. Found one James Allen, but i waited to long and it is gone now. Now I am back to searching.

I have some questions....

1. Is it possible for a VG cut to be better than an Ex cut? I have seen 1 diamond on James Allen that was rated as VG, but HCA rated it as a .8.

2. Are there any inclusions that are worse than others?

3. Is there a chart that shows what could make a GIA cut drop a grade lower on cut (ie, what is the minimum depth or maximum crown angle).

4. is a depth around 60.2% too shallow? or is it ideal to get something that low?


Thanks!

 

[Lorelei]

Hi Newbie and welcome!

My thoughts are below in bold.

1. Is it possible for a VG cut to be better than an Ex cut? I have seen 1 diamond on James Allen that was rated as VG, but HCA rated it as a .8.

Yes it is possible a GIA VG can show a superior visual performance to a GIA Excellent. Don't go by the HCA to select stones though as it is an elimination tool, plus a lower score is not better than a higher one, the aim is to score below 2 then evaluate from there. This is done with images such as Idealscope plus trusted vendor and or appraiser input, then lastly, your own eyes, taste and preference

2. Are there any inclusions that are worse than others?

Depends, yes there can be such as extensive surface reaching feathers as an example but it depends also on the clarity grade, VS2 are generally pretty safe for both 'eyecleanliness' and durability where inclusions are concerned - but there can always be the odd exception so this is a generalization.

3. Is there a chart that shows what could make a GIA cut drop a grade lower on cut (ie, what is the minimum depth or maximum crown angle).

b]Yes, I will post a link for you. https://www.gia.edu/facetware/ [/b] Looks like you might have to register to access it now.
4. is a depth around 60.2% too shallow? or is it ideal to get something that low?

No, that depth is fine providing all the other proportions work well. I look for depths around 60 - 62.4% give or take a bit, and sometimes even a little shallower or deeper depending on the type of stone.

If you have a stone in mind, feel free to post all the info you have or the link here, then we can help you with it.

 

[yssie]

ditto Lorelei.


I had a GIA VG cut that had AGS0 proportions (deep crown out of GIA's EX range, shallow pav). Yes, it does happen, but as Lorelei says don't use the HCA to judge the merits of one stone over another - it is a blunt weeding tool only. Here is an article about GIA EX cut that will help explain why some VGs can be less leaky than some GIA EXs: https://www.pricescope.com/journal/laboratory_cut_grades_what_report_doesn%E2%80%99t_show That said, no GIA EX is going to be flat-out ugly when viewed IRL with two eyes, it is a case of determining better vs. best rather than good vs. bad..

 

[newbie12345]

Thanks!

When you say it's a weeding tool, do you mean it's there to simply say whether or not to even consider the diamond? Also, if I get it from James Allen, do they provide those scope images? How to read them?

 

[stone-cold11]

yap, to weed out the not promising stones then request for idealscope image, since you can only ask for 3 from JA.

How to read idealscope image.
http://www.ideal-scope.com/1.using_reference_chart.asp

 

[Lorelei]

Thanks!

When you say it's a weeding tool, do you mean it's there to simply say whether or not to even consider the diamond? Also, if I get it from James Allen, do they provide those scope images? How to read them?

Ditto Stone and Yissers, the HCA is used for rejection not selection, the aim is to use it to see which stones score 2 or below, then further evaluation is done with images such as Idealscope etc. So yes, the HCA lets you know if the diamond has purchase potential but it does not give you enough info to let you know if it is worthy of purchase. That has to come from images, trusted vendor/ appraiser input then lastly, your own tastes and preference.