Diamond Color Chart

[JohnQuixote]

Carrot,

Why don''t you place this reply in the FAQ thread for discussion?

 

[JohnQuixote]

Apparently Carrot can't post in the FAQ thread right now, so for purposes of discussion I hope a small hijack is ok.

The post in question is located here.

Carrot's reply:

Date: 6/28/2005 3:11:33 PM
Author: carrot
John

After reviewing the FAQ link, I find the proposed explanation unclear. If I came across such a definition on a vendor's website, I would find it evasive. (1) It could be understood as setting the stage for misunderstandings or perhaps establishing a 'back door' for those who might try to sell diamonds as eye clean when in fact they aren't. (2) Further, the article mixes lab report grades with the term 'eye clean' when the two cannot be consistently related. Clarity grades are used to determine the rarity and value of a diamond and ultimately its selling price. 'Eye clean' has a distinctly different purpose.

The term 'eye clean' does not need a voluminous explanation. (3) A stone is either eye clean or it isn't. Inclusions can either be seen in or they can't. (5) What consumer would be satisfied if someone sent them a diamond advertised as eye clean when the consumer could see an inclusion in it?

Certainly one would not use a person with deficient eyesight to determine if a stone was eye clean, nor would they evaluate it in a poorly lit room. Further, a loupe does not make an inclusion more visible to the naked eye. In fact, especially for the inexperienced, it would be entirely appropriate to use a loupe to locate inclusions to simplify the process of determining whether the inclusions can be seen with the naked eye or not. All it would do is shorten the time involved in making the determination.

Further, many settings provide at least a partial side view of the stone. (6) Thus, if a diamond is eye clean from the top but not the side, this should be clearly indicated. If a vendor wants to make the point that an inclusion can be hidden behind a prong, that one thing. But if an inclusion can be seen without magnification, this should be clear to the purchaser in advance.

I've added numbers for ease of reference

(1) Actually, the purpose is an attempt to clarify precisely, in order to set the stage for complete understanding. This allows everyone a baseline for judgment. If their own definition is different they are empowered to voice that. Without definition they aren't.

(2) The reference to the AGS “distance of most distinct vision" was to illustrate agreement on the near point of accomodation as it relates to human eyesight. This distance of judgment (25 cm) has been embraced by the military and other fields for many purposes other than diamond grading. This judgment distance has been long-standing in Brian Gavin's family.

References:

http://www.books.md/N/dic/nearpointoftheeye.php
http://www.swc.cc.ca.us/~jveal/PHYSICS/Phys274/thin_lenses.htm
http://badger.physics.wisc.edu/lab/manual2/node19.html

(4) With respect, I disagree. You might see inclusions that someone 20 years older cannot. A 12 year old may pick them up where you cannot. Someone with 20/10 vision may see something the 12 year old cannot. That same person may see the inclusion in fluorescent light but not in direct light. Which of those definitions is correct? None of them are and all of them are. It varies with eyesight, distance and lighting (the premise of the post).

(5) Exactly. This is why we believe in a clearly stated, transparent definition. If your definition is not the same we can communicate so that we don’t send you a diamond that doesn’t meet expectations. The fact is that some diamonds are more clean than others within a grade (and some cross the lines). Our open definition provides a baseline for judgment and has allowed us to qualify the customer - to better to serve his/her needs - for many years.

(6) I'm sure you know that diamonds are clarity graded in the face-up position. Even a VS diamond may have a side-visible inclusion (though rare). This is something I will add to the original post - and is also a part of communication between vendor and client.

Diamonds vary dramatically. Open communication must take into consideration different eyesights, definitions and tastes. Any advertised definition may come under fire... It is the OPEN COMMUNICATION that is the focus.

My quote in the post indicated "This is a logical and reasonable judgment for our purposes. We respect the right for others to arrive at their own definitions. However you define it though, a working understanding and communication between buyers, sellers and appraisers is critical."

I hope it's clear that we are not trying to determine a definition for every person on earth. On the contrary - we must find a logical method to create a definition whereby we can communicate with every person on earth

 

[carrot]

My apologies, I did not intend to hijack the thread at all. I thought the subject had changed to clarity.

I was not taking exception to the viewing distance issue. My point is that a determination of "eye clean" should be made by someone having normal, uncorrected vision, one who does not need glasses of any type, and who is familiar with what diamond inclusion look like. It would make no sense to me to ask a person with deficient vision to make a determination if a diamond is eye clean in order to attach that label for a prospective customer. The fact that vision typically decreases with age is irrelevant. Simply assume that the determination will be made by, and evaluated by, people with normal vision.

Further, a simple, general, non-binding comparison to clarity grades might be made regaring the probability of a diamond being eye clean along the lines of: VS1 - highly probable, VS2 - probable, SI1 - possible, SI2 - improbable.

 

[belle]

Date: 6/28/2005 3:11:33 PM
Author: carrot
John

After reviewing the FAQ link, I find the proposed explanation unclear. If I came across such a definition on a vendor's website, I would find it evasive. It could be understood as setting the stage for misunderstandings or perhaps establishing a 'back door' for those who might try to sell diamonds as eye clean when in fact they aren't. Further, the article mixes lab report grades with the term 'eye clean' when the two cannot be consistently related. Clarity grades are used to determine the rarity and value of a diamond and ultimately its selling price. 'Eye clean' has a distinctly different purpose.

The term 'eye clean' does not need a voluminous explanation. A stone is either eye clean or it isn't. Inclusions can either be seen in or they can't. What consumer would be satisfied if someone sent them a diamond advertised as eye clean when the consumer could see an inclusion in it?

Certainly one would not use a person with deficient eyesight to determine if a stone was eye clean, nor would they evaluate it in a poorly lit room. Further, a loupe does not make an inclusion more visible to the naked eye. In fact, especially for the inexperienced, it would be entirely appropriate to use a loupe to locate inclusions to simplify the process of determining whether the inclusions can be seen with the naked eye or not. All it would do is shorten the time involved in making the determination.

Further, many settings provide at least a partial side view of the stone. Thus, if a diamond is eye clean from the top but not the side, this should be clearly indicated. If a vendor wants to make the point that an inclusion can be hidden behind a prong, that one thing. But if an inclusion can be seen without magnification, this should be clear to the purchaser in advance.

i believe the opposite is true. i feel that if a vendor does NOT have established guidelines about what is 'eye clean' they may being evasive. if i can look at a vendor's explanation of what their version of 'eye clean' is, i am confident that when we are discussing the type and location of inclusions, we are both on the same page at least.

from where? across the room? at an arms length away? out of the corner of your eye? of course inclusions can be seen (or not) but where and under what conditions are we viewing from? we need a definition.

again, under what conditions? there needs to be some form of standardization and i want to know exactly how the vendor is making the determination 'eye clean'.
sorry, but a 'yeah, it looks good to me' isn't going to cut it.

(at least i hijacked in color!)

 

[Garry H (Cut Nut)]

Suppose an object is viewed by the unaided eye. As it is moved closer and closer to the eye, the image formed on the retina becomes larger and larger. Eventually, a nearest point is reached for the object at which the eye can still form a clear image.

This minimum distance for distinct vision is approximately 25 cm from the eye. Although this nearest point varies among individuals, 25 cm is taken as the standard distance for most distinct vision; it is called the near point.

As a person grows older the muscles of the eye, which thicken the lens and thus increase its convergence (shorten its focal length), gradually weaken. Consequently the near point moves out with aging.

http://cougar.slvhs.slv.k12.ca.us/~pboomer/physicstextbook/ch14.html

 

[asblackrock]

As an optometrist, I feel I can chip in at this stage.

Garry, 25 cm is not the near point until someone with normal vision has reached their late 30''s.

Our near point changes exponentially with age. When we are very young, less than 5cm is more like it and even at the age of 20 it has only dropped to about 8cm.

A myope (someone shortsighted) will have an even closer nearpoint.

The effective size of an inclusion doubles if the viewing distance can be halved.

"Eye clean" is therefore a very, very loose term.