Gem grading, why can''t we come up with a system?

[Sagebrush]

Politely,

Fact is, as you say, its a jungle out there. In every transaction we make the potential of over paying or getting cheated in quality exists. The plumber, the butcher, the heart surgeon. When we buy drugs, cars, and on and on. Boy would I like to see a system for grading plumbers. Point is you gotta trust someone and your sucess in making that decision conditions a lot in life.

Buying a gem is like buying a painting. Unless you go to the sales at the Holiday Inn and buy by the square foot you hardly have a benchmark. Why is Van Gogh''s Sunflowers worth more than Elvis on velvet? Because the willing buyer paid the willing seller.

I don''t agree that the expectation of fraud is higher in the jewelry industry than elsewhere. That seems to be the suppressed premise throughout your analysis. Remember the 20/20 story? I know for a fact that they went to a number of jewelers who did not switch stones but that wouldn''t have made a story. The level of ignorance, among jewelers, is fairly high regarding anything that isn''t a diamond but, jewelers as a group are no more honest or dishonest than anyone else.

 

[valeria101]

Date: 8/22/2005 7:17:44 AM
Author: Richard W. Wise

It there were a uniform grading system in the fine arts, Picasso would have ended up a begger in the street.

Well, he didn't end up on the streets but quite a few now famous artists did!

It may make an interesting argument to notice that this was less likely when painting was a guild-based craft (hence relying on a set of widely recognized and self enforced standards) than it is for modern painting.

That story (the history of aestetics, perhaps) is a bit long and I am not an expert there either. As much as I know, the analogy sounds intriguing.

 

[Sagebrush]

Ana,

Had the standards of a guild remained in control, artists would still be painting in a Sixteenth Century style. Picassso would never have gotten his foot in the door. Progress involves the breaking of established rules the violating of time honored cannons.

 

[Yuri]

Richard Hughes:

An even greater problem with colored stone grading than that of personal preference is the notion that a colored stone has a ''color.'' In reality, it is an extremely complex object which presents the viewer with a mosaic of colors and color sensations...

Dear all,

Apart from grading of color that already discussed in this thread I have a couple of questions about color distribution, the phenomenon that Richard Hughes has touched in his post. I am posting several sapphire pictures here. All of them are different in terms of color distribution. Light areas and dark areas are distributed on the stones surface in different ways and it can be described as “window”, “good distribution”, “worse distribution”. Even if we take apart that these stones are different in color, shape, internal growth zoning and that all pictures are taken in different conditions, after all this color distribution difference remains. My question for experienced colored stone dealers: Up to what level you consider color zoning and color distribution as appropriate, or in other words which of these stones you can buy for your inventory (please understand that this is not a real offer)? And why?
And very similar question for experts: What kind of color zoning is allowed (maximum) by color and by area for highest quality stone?

Maybe I do not properly use terminology because color zoning is usually understood as internal crystal growth zoning and I mean that a stone without internal growth zones has color distribution. What is the proper word?

Yuri.

 

[PrecisionGem]

Just wondering, do we really want a fixed grading system? I was in a local jewel''s shop yesterday while he was trying to sell a guy a 3 stone diamond ring...past..present...future... anyways, the customer seemed pretty sharp and was asking all about color of the stones, clarity etc, and taking notes. I bet he wasn''t home more than 10 minutes and he was online plugging in all the specs of the stones and getting prices from 100 other vendors. Buying diamonds seems to be the same as buying gas. 87 octain, 89, 91 or 93... take you pick, here is the price.
This seems to loose it''s sparkle to me. With the colored stones there are many other factors and personel prefereces involved, maybe it''s better that way.

 

[Sagebrush]

Yuri,

The face of a gem is far from uniform. It is a complex mosaic, a crazy quilt of color. The standard is perfection. That is, a stone with a uniform appearance, without any appearance of texture (faceup zoning), multicolor effect (tonal variations of hue)or lack of brilliance due to cutting defects. 1,2,4,6 show an uneven distribution of color faceup that appears to be the result of zoning. 3 & 5 are windowed but I don''t see either zoning of multi-color effect on my monitor.

No matter, the ideal is a uniform distribution of color and brilliance. Anything less, effects beauty and therefore effects value in a negative way. Suggest you take a look at the free chapter on sapphire posted on the Secrets Of The Gem Trade website (link below)

 

[Sagebrush]

Precison Gem,

I think there is some misapprehension on the part of dealers regarding the creation of a colored stone grading system. They fear it because the believe that it will lead to the commodification (is that a word) of gemstones. Look what has happened to diamond!

Point is, under 10 carats colorless diamond is a commodity. The guy who rushed home and fed the diamond stats into the computer can do that because there are a lot of stones around and pricing out even a D Flawless 1 carater isn''t all that difficult. Try pricing a 1 carat unheated top color Burma ruby. Should be a few on the net but, now add a clarity grade, then add a cut grade. How many eye-flawless excellent cuts would you find? One, maybe!

Take a pink tourmaline, an exceptionally vivid one that shows no brown mask and holds its color in all lighting enviorments...and is well cut with say 80% brilliance. Right now anyone can make that claim but with an objective grading system how much fewer the options would be.

A colored stone grading system would definately make it easier for the consumer to seperate the wheat from the chaff but the only people who would really loose would be those selling the chaff.

 

[PrecisionGem]

Richard, I agree with your last post here. THe problem exists with consumers have no clue, and dealers who tell them anything. I had one lady at a show tell me my Aquamarines were too dark. SHe said her jeweler told her the "best" aqua''s are the really light ones. Hmmm ... bet he had light stones for sale. I''ll show someone a nice Malaya garnet for a few hundred dollars, and then be told that garnets are cheap and should sell for only a few dollars.
I guess in white diamonds, it''s much clearer how a stone will grade out.

Gene

 

[Yuri]

Dear Richard,

You have very good explanation of color distribution reasons in your book:

Richard''s book citation: The face-up mosaic of a gemstone, however, is far from uniform; each facet may exhibit variations in the gem’s key color. Some facets may appear bright, some dull; some may display a dark tone, others a medium- or light-toned blue.
Multicolor effect has several causes (see Chapter 4). Sapphire is dichroic, i.e., light entering the gem divides into two rays, one violetish blue, one greenish blue. In addition, the stone may be zoned: colorless zones are juxtaposed against zones of color. Light rays passing through colorless zones lose color. Also, the pavilion facets of the gem cause a light ray entering the stone to reflect at least twice within the stone, absorbing color as it goes. End of citation
You describe several reasons of color distribution, and I try to concentrate only on the reason that different rays have different paths and absorbed by a stone in different ways. The point is that cutter can be smart and cut a stone in order influence on its appearance.

6 sapphires on my photos are selected without internal color zoning, they have different color zoning because of cut. I am understand that an ideal stone should have ideal even color distribution but in the real world there is no ideal can be achieved and every real stone has uneven distribution of color. Please look at the pair of sapphires at the your webpage http://www.secretsofthegemtrade.com/chapter_22_3.htm
They are matched as a pair but one can easily see different color distribution in these stones.

So my question is where is limit of good looking stone? What king of color distribution is still considered as appropriate?

 

[MingmehDorji]

Hhmmm.........

Diamond grading has been there for over 60 years. Is there a standards today ??? or Standardization of grading Diamonds ????

GOD uses one types of light source,10 times microscope power, own master diamond sets, HRD uses another types of light source and 10 times Loupe and another different Master diamond sets,and so does EGL and others !!!!!!!!!!

60 years, and mind you, it is one life time (many even died earlier) than 60 years old) , and yet GOD cannot come down to meet the Earthlings, to discuss and agree to a stadard.

WHY ???????????????? why ??????????? Why ????????????????

And now Color Grading Standardization ?????????????? Out of your mind !!!!!!! You are crazy !!!!!!!!!!!! Just Crazy !!!!!!!!!!!!!!

Even now GOD proposes the Israeli system, will others agree and follow ?????????? Ehhhhhhhhhhhh ???????????? eeeeehhhhhhh....???

Mind you, it is just all E.....G......O. That BIG Ego !!!!!!!!

It will take another 100 years down the road, where all our ashes becomes gems, and yet there will still not be any Standarzation of Color Grading.

Theory, Hypothesis are all over there.

Even Dick has his views on Burning (heat tratment of Rubies/Sapphires) where he will not budge even to change a word in his Gem ID Certificates, in those old days.

Dorji.