What is Ideal?? Help

[neotao]

ok.. so it is 2:30am and I''m still at work. This is the only time I can be alone and study about the diamond thing without my gf (hopefully future fiance) finding out.

I''m a bit overwhelmed. I''ve probably spent about 15 hours of serious study about diamonds. I have read the goodoldgold tutorial (nice one btw) and a few of the others. I live in NYC so I popped into a few Diamond District shops as well as tiffany''s.

Here is what I have to work with. My max budget 8K. I want the most brilliant and firey stone as close to 1.2 ct as I can possibly have.

I want to stay no lower than G and VS2. I have learned enough to realize that I cut is the most important so, my priority is on cut.
sorry.. i''m rambling.. its late... I''ll get to the point.

From all the sights and people that I''ve talked to, it seems that there is not a clear definition of what proportions are ideal. For example, I''ve gone through several stones and applied the cutadvisor on pricescope ( https://www.pricescope.com/cutadviser.asp). Just when I thought that I was starting to get a benchmark for quality, I looked at a sample stone''s dimensions that is supposed to be AGS Super Ideal,

crown = 34.5
pav ang = 41.1
table = 57%
depth = 60.9

I plugged in these numbers into the cutadviser application, and the results were that the light return, fire, and scint. are very good. (Shouldn''t they be excellent??)

Also, one guy at the Diamond district told me that he hasn''t heard of pavillian angle mattering. Just the crown that counts... Some of the guys I have talked to make me feel like a fool when I try to get specs about dimensions. They don''t seem to really want to educate me, just make a quick sale..

I did go through some H&A stones on goodoldgold, and the results of the H&A brilliantscope seemed to match the cutadviser. So, it seems that I can''t really trust the AGS dimensions. Also, how come some jewelers don''t want to or don''t give proportions?

So, what I''m really asking is does anyone have any suggestions for me... Also, should I order an ideal-scope?

Any help would be appreciated.

Thanks

 

[pricescope]

Neotao, welcome to the forum.

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crown = 34.5
pav ang = 41.1
table = 57%
depth = 60.9

I plugged in these numbers into the cutadviser application, and the results were that the light return, fire, and scint. are very good. (Shouldn't they be excellent??)
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These proportions are within AGS ideal range so many in the industry will say that this stone is ideal cut. However, if you’ve read tutorial on AGS Ideal Cut already, you probably know by now that AGS cut grading system is not perfect.

Combination of 34.5° crown and 41.1° pavilion angles results in noticeable light leakage under the table comparing to Tolkowsky proportions. See picture below.

Cut Adviser system penalizes light leakage. That’s why you didn’t get the top HCA score for this diamond. Note: it is still Very Good cut diamond.

You also can download GemAdviser and play with different samples of diamond proportions including 34.5° crown and 41.0° pavilion and 34.5° crown and 40.75° pavilion.

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Also, one guy at the Diamond district told me that he hasn't heard of pavillian angle mattering. Just the crown that counts...
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Pavilion angle is very important because light should reflect twice from pavilion facets in order to return to observer’ eyes. See e.g. Crown and Pavilion

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Also, how come some jewelers don't want to or don't give proportions?
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They don’t use to it, don’t have equipment or just don’t want to spend time on this.

Ideal scope can be handy if you plan to shop in B&M stores and review/compare different diamonds yourself. You also have a chance to find nice looking diamond outside AGS ideal range and save some $$$

Good luck and post your experience here