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Fire, Brilliance, Scintillation general question

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justme

Shiny_Rock
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Dec 5, 2002
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Came upon this while researching - can anyone comment?

Any diamond proportioned between the following parameters will have, to the naked eye, exactly the same light refractive properties to one another:

Table diameter: 53 to 61%
Crown height : 11 to 16
Pavillion depth: 43 to 44.5%

The so called 'Ideal' cut and 'H&A' have these approximate proportions:
Table diameter: 53 to 56%
Crown height: 15 to 16%
Pavillion depth: 43.5 to 44

They show no advantages as to what 'sparkle', 'fire', 'brilliance',or scintillation is concerned if compared to stones with a different set of proportions.

The main difference between the two will be in the size of the diamond, as an example a 1.03ct diamond cut to very stringent parameters, as those of the 'super ideal' or 'H&A' will look around 20% smaller than another 1.03ct
stone cut to less stringent parameters. Also since more expensive diamond weight will have needed to be removed in order to cut to these more stringent parameters the end price will be more expensive as well.

Also there are increased high labour costs.

You may now ask me, why then did we decide to cut these stones?

Well the answer is we didn't, we were forced to my market conditions emanating from Japan some 13 years ago now when some dealers, in order to control the very lucrative Jap market decided first to invent the 'excellent cut' then
the 'ideal' cut a transition to the 'super ideal' leading to the phenomena of the 'H & A' effect as seen through a simple polaroid filter, similar to the sun glass lenses of the same name.

All this was built up, through advertising and slick marketing in order that the public believe that this type of cut is best.

You may now ask, but anyone could cut their diamonds to these very high specifications and compete, well again the answer is no. It needed a very high degree of cutting expertise to cut these stones and this is where we came in those 15 odd years ago.

Indeed we were approached by a top Japanese wholesale dealer who entered an exclusive manufacturing partnership with us in order to get these very exclusive diamonds.

For years we had a near monopoly on their manufacture and the world's biggest workforce exclusively cutting to these high parameters so we know what we are talking about.
 

Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,271
Greetings justme,

That advice sounds nothing short of ridiculous. Let me answer point by point and demonstrate just how ridiculous this information is.


Any diamond proportioned between the following parameters will have, to the naked eye, exactly the same light refractive properties to one another:

Table diameter: 53 to 61%
Crown height : 11 to 16
Pavillion depth: 43 to 44.5%


Attached to this first response is a gem file (you'll need the gem reader software) of a stone with a 14.8% crown height, 57% table and a 44 % pavilion. This falls within those parameters above. The file I sent is a simulated FireScope image which shows light return/leakage of what that prospective stone could be like. If you do not understand how to interpret these images a cursory reading of my page on the subject will help. Here is that link. http://www.goodoldgold.com/the_idealscope_firescope_tm.htm



The so called 'Ideal' cut and 'H&A' have these approximate proportions:
Table diameter: 53 to 56%
Crown height: 15 to 16%
Pavillion depth: 43.5 to 44


While I have seen H&A's cut to these parameters these do not represent the "norm" and very very very few will have crowns as high as 16% and NONE will have pavilion depths of 44% so this information is way off. 43.8% is the cut off for an AGS "0".

They show no advantages as to what 'sparkle', 'fire', 'brilliance',or scintillation is concerned if compared to stones with a different set of proportions.

Of course they will not show. They can't.:knockout:

The main difference between the two will be in the size of the diamond, as an example a 1.03ct diamond cut to very stringent parameters, as those of the 'super ideal' or 'H&A' will look around 20% smaller than another 1.03ct
stone cut to less stringent parameters. Also since more expensive diamond weight will have needed to be removed in order to cut to these more stringent parameters the end price will be more expensive as well.


The H&A will look 20% smaller? 20%??? I'd be curious to know where you got this very faulty info.

All this was built up, through advertising and slick marketing in order that the public believe that this type of cut is best.


To be honest when I first heard of H&A myself I thought it was all hype and another gimmick. In the over 2 decades I've been in this biz I've seen alot of fluff so I approach each new concept, cutting concept, fluffy names with a strong dose of skepticism. Thank God I have the tools to be able to put these to the acid test and *see* quite critically whether a companies claims live up to what they are saying. There are DEFINITE bennies to the H&A diamonds. It is not fluff. There are definetely H&A's that are more brilliant, fiery and scintillating than others but all of them are a heckuva lot more beautiful than the common crap that's being sold today on the market.

Download the gem reader software first here at this link and install it. https://www.pricescope.com/MSU/gadviser.asp

Then click on the little file attachment below this response. Check out the simulated FireScope image. Then compare that image to the next one I'll post and you'll see some significant differences.

btw .. in the example I used a 1.03ct sized stone.

Peace,
Rhino
 

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Rhino

Ideal_Rock
Trade
Joined
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Messages
6,271
Ok ... this next example (taken from the parameters given from your source) has a 61% table, 15.8% crown height and a 44.5% pavilion.

Check out it's simulated FireScope image.

btw ... these are 2 examples of stones that I wouldn't spend my money on ANY DAY. I pass up lemons like this frequently and I would also add that while I'd pass em up, THESE 2 STONES APPEAR very different optically.

Peace,
Rhino
 

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Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,271
Here is an example of the types of stones we hunt down when making purchasing decisions. What's neat is you can open up these .gem files sidy by side and do comparisons as well.

Hope this has been of help.

Rhino
 

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Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,271
And while I'm having fun :) ... here is an example of an H&A diamond that we passed up recently. It's H&A pattern was crisp but note in the attached file (in the simulated FireScope image) the absence of the dark red under the table (whereas the last example had dark red under the table). That lighter area indicates leakage, which indeed this diamond did have that leakage under the table and turned out to be a reject here. Not that this is an ugly stone and by no means is it. It would blow away the first 2 examples I gave above. Thing is, I have access to more of these kinds of stones and it's very easy for me to sign for them. When I'm purchasing for stock and laying out the $$$ I only do so on the rarest cut qualities.

Hope this has helped.

Peace,
Rhino
 

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