 |  |
| Sign in or Register Home |
|
|
|
| Buy | Sell | Education | Forum | Directory | Blog | |||
 |
||||||||
|
||||||||
| HOME : FORUM : EDUCATION : DIAMONDS : Re: Importance of Diamond Cut Grading |
|
|
|
Thread Tools | Search this Thread |
|
The Importance Of Diamond Proportioning
Post#1 @
10-06-01
, 02:58 AM
The next three postings demonstrate the importance of diamond cutting and proportioning. The first is a diamond that is too deep, the second is too shallow, and the third is IDEAL cut. I thought with all of the discussions about cutting and proportioning some might like to see that actual results of proper cutting. These are actual photo demonstrations taken on digital camera of the GIA proportion analyser and not just graphic images. These are real light path photographs showing what happens with diamonds that are correctly and incorrectly proportioned. I hope this is of service to someone here. YourGemologist http://www.YourGemologist.com
[Edited by YourGemologist on 10-06-01 at 02:11 AM] |
||
|
|
|
Re: Diamond Cut Too Shallow
Post#2 @
10-06-01
, 03:00 AM
Here is a diamond that has been cut too shallow. Notice that the light, like the stone cut too deep, is leaking out the bottom. This diamond, regardless of the quality, would not be very brilliant. YourGemologist http://www.YourGemologist.com
|
||
|
Re: Diamond With Proper Proportioning
Post#3 @
10-06-01
, 03:05 AM
Here is a diamond that has been cut properly. Notice that the light is going in the top and going out the top. And regardless of where it goes in the stone, the light will all go out the top. Making this diamond brilliant even if it is below the first two in clarity and color. I hope this demonstration is of service. YourGemologist http://www.YourGemologist.com
|
||
|
Re: Importance of Diamond Proportioning
Post#4 @
10-06-01
, 03:40 AM
Actually Garry, these photographs graphically demonstrate the path of light through a diamond in the various deviations from IDEAL cut. The fact that the medium is the one used to demonstrate the concept is of little or no importance. The fact remains that this demonstration is indeed factual for the importance of demonstrating the path of light in the various cuts. A diamond that is cut with a depth that is beyond ideal will indeed leak light, as will one cut too thin in a spread cut. Only the proper proportioning will create the maximum level of light path control to maximize brilliance. That is all this demonstration seeks to prove. And I think it does it quite well. I think you are over analyzing the intent and purpose of the demonstration. And, given the fact that these photographs specifically substantiate the purpose and intent of your "Ideal-Scope" I am a bit surprized at your reaction. But everyone to their own. The demonstration stands on its own merits. With Respect, Robert James FGA, GG YourGemologist http://www.YourGemologist.com [Edited by YourGemologist on 10-06-01 at 02:47 AM] |
|
|
Post#5 @
10-06-01
, 07:45 PM
Let me see if the poor, poor, and much maligned Rodentman understands this: Perspex is a type of plastic with a different refractive index than diamond and therefore Garry assets that the test is invalid, or misleading. Is the refractive index close enough so that the principle is supported, that cuts that are too shallow or too deep leak light? Isn't this generally accepted as factual? I agree that the indicies may be different enough to require an exaggeration of the angles and percents. Am I close? The Rodentman |
|
|
Re: Points Well Made and Well Taken
Post#6 @
10-06-01
, 07:53 PM
Your points are well made and well taken, Garry. I think my demonstration was more of a basic nature for the consumption of consumers, and you are well beyond that in both theory and practical knowledge. Perhaps a re-wording of my original intoduction would have better directed the intent and purpose of the demonstration. But if it at least gets people to understand that poorly cut diamonds equal less brilliance, then the demonstration was of some value. Thanks for your excellent thoughts and information. YourGemologist http://www.YourGemologist.com |
|
|
You are correct Rodentman
Post#7 @
10-06-01
, 08:01 PM
The purpose was indeed to simply show how too deep and too shallow will cause light leakage. The problem was most likely my equating the demonstration too closely with an actual diamond reading. That was unintended if it indeed is the case. As there are many here who are very well trained and experienced expert gemologists and physicists, and others who are new and need to learn from the beginning, the presentation of information can sometimes become convoluted. As was the case on this instance. My purpose was simply to make a demonstration of the importance of diamond proportioning for consumers. Not to start a technical debate on the physics and dynamics of light travel in a crystallized carbon medium. The subject was carried far afoot of its intended purpose. YourGemologist http://www.YourGemologist.com |
|
|
Post#8 @
10-06-01
, 08:24 PM
Could not the same demonstration be done with a real diamond, or is this technique and equipment made for large, "demonstration-sized" pieces? The Rodentman [Edited by rodentman on 10-06-01 at 07:57 PM] |
|
|
Post#9 @
10-06-01
, 09:17 PM
Garry Post a sketch of a real diamond cut "too shallow", showing where the light REALLY leaks out. All will be revealed to rodentman! R/A |
|
|
Lets get down and dirty on proportioning grading
Post#10 @
10-06-01
, 09:58 PM
Rodentman, Given the right set of circumstances and equipment the demonstration could work on any transparent material capable of transmitting energy of almost any wavelength through a medium of sufficient transparency. Unfortunately, this was was just a simple consumer oriented demonstration which 10 out of 10 consumers that I have shown it to walked away understanding. The issue has become overly burdensome due to some admittedly wonderful minds wishing to take the matter beyond the simple context of its intent. (have I said that already) However, truth be known, the advanced concepts being presented here fail to provide for several variables that will affect even the most advanced of inventions regarding diamond cut and proportioning. First is the wavelength and amplitude of the energy being tested as it passes through the medium. These could affect the test results as the critical angle of the medium might react differently to various energy wavelengths and amplitudes. Second is the density of the medium, and the variables relating to the density, as is the case with corundum with a higher density than diamond, but a lower refractive index. Ruby is an aluminum oxide with chromium impurity in the lattice while diamond is made of a tightly bonded 18 atom cubic unit that is far more dense to energy being transmitted through it. Ruby has a higher specific gravity due to volume, yet diamond has a higher refractive index due to stronger atomic bonding. Assuming we are talking about diamonds here, please refer back to #1 at the first of the paragraph. Third is the angle at which the energy is directed at the medium. Since we are dealing with a 3 dimensional universe the source of propogation and angle at which it strikes the medium will have an affect on the refraction of the energy into and out of the medium. The test results would have to be standardized as to placement of energy source and direction of travel of the energy to insure that all results were controlled. And finally, internal anomolies in the crystal struction such as internal stress, inclusions, and anomolies in the crystal lattice structure can and will have an effect on the final energy path. As a result the reliability of any invention or instrument would have to be based on a uniform set of test rules using standardized test conditions, or else the results being claimed by any invention would have to be provisional based on the variables in testing conditions, energy sources, and mediums. To the point the the test results from a VVS1 clarity diamond and a SI2 clarity diamond could vary significantly, allowing someone testing their equipment with the VVS1 stone to get far more accurate readings that someone testing another invention using SI2 clarity diamonds. Not because the equipment was more accurate, but because the medium used was of higher quality...or simply was tested with differing energy sources. Therefore, before any instrument or invention can be considered as accurate to any degree with any medium or energy source, all of these variables must be identified, factored into the equation, and accounted for in any successful evaluation of the proportioning quality of any medium....ie gemstones, or the performance of any piece of equipment. Or, we can view the difference in light leakage in a simple platic model that helps consumers understand the importance of proportioning in diamond grading...where all of this first started. Personally, I spent years studying all of the above and found it not only boring, but turns customers off. So now I use the GIA Proportion Comparison unit to explain things in ways everyday customers can understand. Not to say that the engineers and inventors are not very important parts of the industry. And I certainly have a high level of respect for their knowledge. But if they want to really provide some high level test results of diamond proportioning equipment, I would like to see a report from someone providing the above information regarding the above scientific evidence of performance of their inventions and equipment. Then, I can not only make a better judgement of their invention, but I can also duplicate their test results in my lab and see if their claims hold true. Its all just science. I just choose the fun stuff. Respect to all, YourGemologist http://www.YourGemologist.com [Edited by YourGemologist on 10-06-01 at 09:07 PM] |
|
|
Harsh words to follow:
Post#11 @
10-06-01
, 10:09 PM
If what you show doesn't reflect the actual path and travel of light in a less-than-ideal cut, why peddle this crap. I felt insulted as a consumer when I found out that this "light leaks out the bottom" diagram is bullshit and real diamonds don't "leak" like that. Just because 10 out of 10 understood (or maybe "were duped" is a better way of putting it) doesn't make your diagrams meaningful. Nice try, though. Your heart's in the right place. ...now where's that thread where Sib learnt me about that diagram... |
|
|
Re: Not like a diamond
Post#12 @
10-06-01
, 10:18 PM
Rank Amateur, As an engineer you know that not all scientific test results can be demonstrated to their "n'th" degree so that they can be duplicated on a talk forum on the internet. Indeed, diamonds do "leak" light exactly as shown as far as concept. That they do not "leak" to this degree as an actuality is a matter of interpretation. If you were insulted, I certainly offer my regrets. I have never had a consumer insulted when I tried to shown them a simple concept about diamond proportioning using a simple demonstration tool. In the future, if I post a demonstration, I will start with a disclaimer warning you personally not to look. I make every effort not to insult people these days. Respect, YourGemologist http://www.YourGemologist.com |
|
|
note to self: remove "engineer" from bio
Post#13 @
10-06-01
, 10:33 PM
Robert It's good that you are here. I'll try to step off that wrong foot I started off on. Take a look at this thread (you too, rodentman): http://www.diamondring.com/forums/showthread.php?t=8568 . I think it taught me a lot about these pesky "leaking" rays and that cardboard cutout on everybody's counter (next to the cash register). Let me know what you think. R/A [Edited by Rank Amateur on 10-06-01 at 11:05 PM] |
|
|
Post#14 @
10-06-01
, 10:42 PM
Actually Garry, you simply restated what I had already said, that the tight atomic bonding of the carbon atoms is the cause of the higher RI of diamond in relations to the higher SG of corundum. If I did not stipulate that the 18 atoms have the 4 way bonding, I guess I assumed you would already know that. Please read my post carefully. I think you will find my understanding of molecular structure will withstand any solid evidence you wish to present regarding your invention. I must assume that this "Ideal-Scope" of yours has been tested scientifically in the controlled environments that I discussed in my previous posting. Could we see them here? You may indeed have something quite remarkable. Please provide the testing evidence by which you ascertained the accuracy of your invention, and therefore your claims to consumers. Or perhaps, we could simply solve this problem if you could tell me how I might obtain one for testing. I have my credit card ready if you could let me know how to order one. YourGemologist |
|
|
Rank Amateur: there is no wrong foot, only respect
Post#15 @
10-06-01
, 10:54 PM
Just a note that I have full respect for your position in these banters, as well as Garry's. Garry is trying to sell a $20.00 item that helps consumers identify diamond cut and I say "God bless him for it" I do wish he would not go so far to the edge of personal insult. For a number of years I maintained an Allied Teaching Centre for the GA, and continue to tutor FGA students. His view that: Only his interpretation is the correct interpretation, falls short of healthy scientific debate. And his leaning toward personal insult out of frustration that, as he stated "I won't give up" tends to make me think that he views this as a battle and not a simple exchange of ideas. After all, it was only a simple demonstration tool that the Gemological Institute of America has used for years. Its just not as big a deal as Garry is trying to make it. Unless sales are slow this week for the Ideal-Scope. YourGemologist http://www.YourGemologist.com |
|
|
Post#16 @
10-06-01
, 10:55 PM
Very interesting, but... I'm just a poor accountant (and Oracle Financials guru) who's having trouble accounting for himself. I'm not an engineer, gemologist, or optical scientist. I couldn't even spell GIA or AGS when I got on DT in August. I read pricescope, Johnathan's website, etc. I learned a lot and read the "light leakage" material. I saw Firescope images and bought an Eightstar. No light leakage, the best, etc. I don't want to start that debate yet again, but let me add this: Another path that consumers could take is that espoused by some on DT and certainly by many in stores: If it looks good from 3 feet away, buy it, keep it clean, and forget all the hair splitting scientific crapola. I heard it at the mall today! I don't want to stifle debate or interpretations of scientific data, but isn't there a real chance that people are going to get turned off by this and just let some mall salesperson pick out a stone for them? I spent a lot of time studying this, (for an accountant), and now even I am wondering if what I thought was sound science is questionable. Isn't there enough irrefutable science to tell us what is going to make a diamond look good? Or am I totally missing the point of this discussion? I am becoming confused. The Rodentman |
|
|
Rodentman....YOUR BEAUTIFUL
Post#17 @
10-06-01
, 11:03 PM
Bingo, my friend. Because consumers are getting turned off of these kinds of debate is why they are turning away from knowledgable jewelers and going to the "ain't it pretty, don't you like it" guys. That is why I tried to keep the concept simple, for consumers. After all, you are the one's paying our bills. So if we alienate you with all this hype and jargon, who loses? We do, not you. There will always be some bloke out there selling the romance and sparkle, and forget about the degrees and stuff. You understand this idea better than anyone here. Well done! YourGemologist |
|
|
Post#18 @
10-06-01
, 11:04 PM
Rodentman I don't think science has quite nailed down what makes a diamond "look good"; however, I DO think that science has figured out that light does NOT leak straight out the bottom as shown in the typical diagram. So why keep the diagram on the front counter? Rock on. |
|
|
Why keep it on the counter
Post#19 @
10-06-01
, 11:12 PM
Rank Amateur, Its because you are a scientist who understands degrees and density. Most consumers do not. And a simple demonstration is all they need. With all respect, the point is to sell diamonds, not education consumers with scientific data. Consumers may go to one store to learn about diamonds because someone there is able to go into scientific detail, but they will go the store with romantic appeal to actually do their buying. After 30 years in retail jewelry, it is my humble opinion that the above is very, very true. KEEP IT SIMPLE AND MAKE THE SALE! I don't know of any retail jeweler who makes a living out of educating consumers to the degree offered here. Consumers want a beautiful diamond that will sparkle across the room at the party and make everyone jealous. That's why consumers want to buy diamonds. To show off. As long as they show off, who cares. And consumers.........ARE RIGHT! YourGemologist [Edited by YourGemologist on 10-06-01 at 10:14 PM] |
|
|
Post#20 @
10-06-01
, 11:19 PM
OK, well MY approach to a diamond purchase, or any big ticket item that I am not expert on, is to study and make my best judgment based on what I deem to be believable and credible evidence. I want to make an educated decision, not just one based on someone's words, whether a salesperson, or someone on a forum. Got to have evidence. B'Scope, F'Scope, credible, logical etc. I try to weed out hype and BS. What makes a diamond a top quality diamond; how can one tell if it is worth the $? Gotta be science. A person cut it a certain way for a reason. Not an accident. For what reason was it cut the way it was, maximize weight, profit, light return, etc. The more I read, the more I learn, and the more I conclude that as Ringo said, "It don't come easy..." The Rodentman |
|
|
Post#21 @
10-06-01
, 11:26 PM
If the point is just to sell diamonds, why talk about cut quality at all? Stick to the other three C's. Let your customers look at different stones and pick the prettiest ones. Worked for years and years. No disagreement from me (except on how your explain your pricing). If you are going to start on the light ray stuff, base it a little closer to reality, and give the consumer and his ability to understand a little credit. Show the extra two to three reflections and THEN the light exiting rather than show an overly simplified singlularly refracted light path that simply does not happen. It looks like you took the diagram and then hunted up a material to use in the demonstration that performs like the diagram, never actually considering "real" optics. You brought up Garry's schlepping his ideal-scope, but, say, you don't have a vested interest in your side of this argument, do you?  |
|
|
MY PERCEPTION OF THE PICTURES
Post#22 @
10-06-01
, 11:33 PM
I am not an engineer or any of that either, just a clothing retailer with interest in reading......diamonds are my latest favorite topic. As I was looking at the first 3 pics, I noticed that the light wasn't shining on the diamond in the same spot each time, it looks like the light was moved to get the effect. Now on the shallow or deep cut, if you moved the light to a different spot on the diamond...would it not show a different effect. Just wondering, I'm not into all the technical stuff.....bought my deep cut radiant VS2 diamond and LOVE IT!! |
|
|
3 Questions - 3 Answers
Post#23 @
10-07-01
, 12:16 AM
marriahlyn, If you were to see this demonstration unit in person you would see that it does not matter where the light goes in. (why is everyone being so anal about this little thing. Its been around for about 30 years in the jewelry industry, and it is just to show a concept...not a strategic scientific instrument) Listen up::::::ITS JUST A DEMONSTRATION! The concept behind it is true. If you don't believe it then its OK by me....really!!!!! I won't lose any sleep over your not believing in it....if you won't lose any sleep if I do. :-) Rank Amateur, The proportioning of a diamond has as much impact on diamond price as clarity or color. Its just harder to ascertain and demonstrate for consumers. If you cannot understand that concept, then please, please do what's right for you. Somebody may look at my demonstration and say, "Damn, thats what my jeweler was talking about!" It is for them that I posted this demonstration. If you don't believe in it...Bully for You. Live long and prosper. But the concept demonstrated by this unit has far more implications than Garry wishes to admit. Again, believe whomever you choose. I really don't care. However, just between you and me....YourGemologist.com is a well respected NOT-FOT-PROFIT gemological reference and study site. We have students from the British Gemmological Association and the GIA who visit to get assistance with their studies. I continue as a tutor for the FGA students. And I established this site SPECIFICALLY because we needed a reference site WITHOUT anyone trying to sell a gadget or make some profit by the response. Garry strangely disappeared when I asked for scientific test data on the Ideal-Scope that we could confirm in our lab. Everyone and anyone can draw whatever conclusion from that you wish. I have drawn my own. And Rodentman, it never comes easy. But it sure goes easy if you don't try to make it too hard. But it still amazes me how a rather insignificant demonstration tool can provoke such a huge reaction. And I still wonder....where is the scientific data regarding the accuracy of the claims made for the "Ideal-Scope"? Who else has tested this thing to say that it even works. Who knows...I might get one and make digital photographs of the results and post them here. And we can, "start...all over...again.." Hey, this was great. Respect to all. YourGemologist http://www.YourGemologist.com |
|
|
Post#24 @
10-07-01
, 12:23 AM
I guess we agree to disagree. I hope you 'splain it better in your gem classes than you do to those consumers! |
|
|
'Xplainin to Rank Amateur
Actually, I have a high success rate with both. But I do have a few problem students....hey???....lik e you! (Didn't I say I was going to post a disclaimer for you not to look at my next demonstration????) :-) I know what the problem is Rank Amateur....we need more Heinekens. Then you would understand much better! Nurse! More Beer for me and my friend! YourGemologist |
|
| Read Messages in: | DIAMONDS | All forums | ||||
| Newer: |
|
|
||||
| Older: |
|
|
||||
|
| ||||||
| Thread Tools | Search this Thread |
|
|
| Contact Us - Guidelines - Privacy Policy - Refer a Friend - Top^ |
|
|
