Cut Advisor Question

[Skip12]

Hi Leonid,
I have been having a lot of fun reading the information on your site and using the cut advisor. Your site has moved me from a consumer to a fanatic. I have run into a question I was hoping you could answer. I ran 2 rocks on the cut advisor and the results surprised me. Here they are:
Rock1 / Rock 2:
Table: 56 / 55
Depth: 60.8 / 61.1
Crown: 15.1 / 15.1
Cro Ang: 34.5 / 34.0
Pavil: 43 / 42.6
Pav Ang: 40.8 / 40.6
Gridle: Med / Med
Type: HOF / H&A
Color: D / D
Clarity: VS2 / VS2
Both rocks have excellent sym, proportion, and polish, no cutlet, no flor.
The cut specs on Rock1 appear to be better than Rock2 with the exception of the table. The cut advisor rates Rock2 better. Does table size have the biggest influence over all the other parameters of cut?
Cut Advisor results:
Rock1:
Brilliance: Excellent
Fire: Excellent
Scintillation: Very Good
Spreador diameter for weight: Very Good
Total Visual Performance: 1.5Rock2:
Brilliance:Excellent
Fire: Excellent
Scintillation: Excellent
Spreador diameter for weight: Very Good
Total Visual Performance: 0.7Thanks for the great web site and board on Rockytalky.
Skip

 

[pricescope]

Hi Skip, Thanks for kind words

This is quite a big subject to cover so I'll try to explain shortly and if I'll miss something please ask for more. Ok?

First of all both diamonds are great. The first one Hearts on Fire (correct?) has exact Tolkowsky crown and pavilion angles.The second stone with a bit shallow crown and pavilion angles than Tolkowsky is scoring better on the HCA because according the latest studies these proportions should yield higher brilliance and fire and less light leakage comparing to Tolkowsky and it has a bit larger spread, i.e. looks a bit bigger for the same weight.Im sure you will find these materials interesting to read: www.cutstudy.com/cut/english/document4.htm www.cutstudy.com/cut/english/document4_1.htm
and www.diamond-cut.com.au 56% or 55% table size does not affect the result - both table sizes are excelent.Here is another food for you thought. EightStar diamonds that cut to maximize light return and dispersion (fire) and considered by many experts as most beautiful diamonds has either less crown or pavilion angles than Tolkowsky. Here is an overlay of crown and pavilion angles I found for EightStar diamonds and the Q-factor (www.cutstudy.com/cut/english/document4_3.htm):

This is just an example how theory correlates with the experimental results.Now back to your two diamonds. Garry Holloway believes that diamonds scoring less than 2 are great. Theoretically the second one can be the best but now you have to compare them yourself and see which one you like the most. Since both diamonds are Hearts and Arrows it is important to see how consistent is the H&A pattern. The price can be an issue too of course.If the price is substantial it is also a good idea to show the diamonds to the qualified independent expert.Thanks again for your post and please keep us informed what you will choose and why.leonid

 

[pricescope]

Garry Holloway, www.diamond-cut.com.au (CutNut on this board) wrote the tutorial for our site with the video - www.pricescope.com/tutorial.asp and his cut evaluation system is a background of the Cut Adviser.Garry is working now with scientists and experts from around the world on new cut related stuff. We are very proud to have this 100% new content on Pricescope.Another think you might like is 3D diamond imaging: www.cutstudy.com/cut/english/collection.htm Use IE4-5 so you can use online diamond modelling software to plug the proportions for your diamonds to simulate their virtual images in different conditions. Use angles to be more precise.

 

[Skip12]

Thanks Leonid,
I now understand that the Tolkowsky cut may not be the ultimate as far as visual appearance. I guess that is why eightstar cuts for visual performance as opposed to an exact shape.
Thanks again for the info

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Skip

 

[pricescope]

That's right. Some of the EightStar diamonds are outside of AGS-0 propotion range but it doesn't make them less beautifullleonid

 

[Skip12]

WOW! Thanks Leonid! Now that's a study on cut!!! http://www.diamond-cut.com.au/ ------------------
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