Comment

[bela1972]

As I mentioned in an earlier posting diamond technology in general and visual performance in particular is no rocket science.

The visual results obtained by the manipulation of crown and pavilion angles are well known and documented by both the diamond cutters and the GIA.

GIA research and development have done extensive research using Ray Tracing software
They can easily grade cut quality by visual performance.

Why then do the GIA make no comment to proportion and the resulting visual performance on their certs?

Why do AGS promote the Idea that the range of dimensions that produce optimum results is very narrow?

The reason is market share, As long as GIA withhold critical dimensional data they are assured of being the cutters choice,

The AGS targets the other end of the market all be it a much smaller market, This is the “Ideal Cut” fanatics that have made AGS a status symbol

EGL on the other hand achieve their market share by “soft grading”

Why do we say the HCA is a good tool for consumers but of no real value to cutters or the diamond trade?
While we applaud all efforts to help consumers make informed choices we found the mathematical macros very limiting.

The reason is the HCA is only taking into account at most 18 of a possible 58 facets. We have found that light return can dramatically change by manipulating the 40 minor facets (the star facets and upper and lower girdles) that are not considered by the HCA.

Our instrument of choice would defiantly be the Brilliance Scope as it shows the effect of light return when changes are made to any facet. It can easily tell you if a facet is acting as window or a mirror.
The Brilliance Scope does not base its results on calculations. It reads the actual light return

No instrument that doesn’t actually measure or test the individual diamond can provide accurate data.
If the item doesn’t actually “see” the diamond, it’s nothing more than math and guesswork..

 

[oldminer]

There are severla things in your post I'd disagree with. This one is especially noticeable:

"GIA research and development have done extensive research using Ray Tracing software. They can easily grade cut quality by visual performance."

The GIA does not grade "cut quality" by light performance because cut quality is not determined by light performance alone. That is not an accurate statement. Cut quality has to do woith durability and depth to width ratios. Cut quality has to do with girdle thickness. Cut quality has to do with creating a pleasing outline. Beauty is not determine by ray tracing or a study of brilliancy and light return. These are only components in the overall quest for answers that we do not yet have in total.

 

[oldminer]

The other bone to pick is this one:

"Our instrument of choice would definitely be the Brilliance Scope as it shows the effect of light return when changes are made to any facet. It can easily tell you if a facet is acting as window or a mirror. The Brilliance Scope does not base its results on calculations. It reads the actual light return."

Again, this is no way to select a diamond. This device gives only a partial answer to "cut quality" and it is a non-numerical answer anyway. How would one compare two very finely brilliant stones that get very similar ratings. The device does not choose, so the resultant choice is still left to subjective choice. The BrillianceScope does not take durability of the cut, depth to width ratios into account or girdle thickness. All of these, again, serve as integral parts of "cut quality"

Partial answers are not unwelcome ones, but to offer the BrillianceScope as the way to select a diamond for cut quality is to stretch the usefulness of a device that cannot be expected to do the entire job.

Even when the day comes that we have totally rep[eatable and numeric result devices, they will not serve to dictate entirely what is most beautiful or attractive. This is a matter of personal taste that we ought not remove from the choice of consumers. Give them information upon which to make intelligent selections, but remember the ultimate selection is up to the person buying or wearing the diamond.

 

[fire&ice]

----------------
On 10/13/2002 6:38:56 PM

Even when the day comes that we have totally rep
----------------
[/quote>

At the end of the day, this is the only thing that matters. We are the end user. The tools are an aid to perhaps predict what a diamond may look like. I understand the cut crusade. Cut was not even mentioned to us as being important (1982) until we saw a Lazare Kaplan stone - it blew me away - and it became clear to me that none of the stones we were looking at were well cut..when I expressed my cut curiosity & concern - it was addressed quickly to keep my business.

While the research is appreciated & a good thing, the "level" of which one declares a good stone is out of control. As a consumer one must balance all factors of selecting a stone....and some of us may make a conscious decision to NOT pay a premium for an "ideal" stone....especially when one's eye see little difference. Quite frankly, my OEC (big score on HCA - 4+ and more because of the larger culet) is extremely charming....maybe I don't have a diamond viewers eye. The notion that an average consumer can pick an undervalued stone is just not the norm and would require luck & alot of time. Most of us can't get the specs on hundreds of stones and ask that they be sarined, brillancescoped, appraised & available for ideal scope. We also don't have the time!I think we would drive the diamond dealers over the edge....and ultimately drive up prices - JMHO.

I'm sorry to get this off my chest. I'm just a realist & not an idealist. As I said before, the world needs both. I'm not advocating the cutting or purchase of poor cut stones....just that their is a happy medium out there....and tons of personal preferences. I'm in the minority that wanted a thicker girdle at the expense of MM size. I wanted to set in a four prong and felt (in my mind) more secure w/ thicker girdle.

..just a different spin. And, no I am not saying that my choices are right for everyone....just my choices.