Are total depth calculations always correct???

[diagem]

This thought keeps popping into my mind every-time I measure extra long shaped Diamonds... (especially small sizes 0.01 to 0.15 ct.).
I am highlighting smalls as the girdle plane of a small Diamond has a significantly bigger impact on the depth vs. bigger sized Diamonds.

Naturally..., the longer the shape of the Diamond, the deeper the depth because common practice for measuring depth % is (depth mm. divided by width mm.)

I just finished cutting very long shapes (radically long) and noticed the depth are averaging well above 70% (even close to 80%)..., the Diamonds are very pretty looking but the numbers are not... (dealers who are concerned about #''s cant understand the depth factor on these type of stones.)

Shouldnt we take the length of radically long shapes into consideration when calculating depth%???

I would like to hear some opinions from the experts on this issue...


Thanks,

 

[Paul-Antwerp]

Your question first confused me, but reading your post, I understand what you mean.

The reality is that the whole procedure of calculating total depth is mathematically very easy, but it offers no information on the cut-quality, and as such, it is of no use.

Unfortunately, many people in the trade are so used at working with this figure, simply because it used to be one of the only two numbers on a GIA-report, but it means nothing.

Like you say, by calculating depth as a percentage of the smallest diameter, there is no standard basis to work with. The longer your length, the deeper your depth-percentage.

I have written various articles in the Pricescope Journal, mainly on depth in princess-cuts, but much also applies to other fancy shapes.

For instance, cutters of many proprietary cuts have the total depth calculated in a different way. Very often, they calculate the percentage with the longest diameter (from point to point) as the basis, which greatly reduces the depth-percentage. Many people are confused by this, and think that a lower depth means a higher spread.

Also, too many people, in and outside of the trade, are comparing the depth of rounds (around 60%) with the depth of fancy shapes, not realising that the calculation is not the same. Rounds'' depth-percentage is a percentage of the average diameter, in fancy shapes, it is a percentage of the smallest diameter. Big difference.

All in all, this is a very sad situation, I think.

Live long,

 

[diagem]

Date: 11/8/2007 6:27:47 AM
Author: Paul-Antwerp
Your question first confused me, but reading your post, I understand what you mean.

The reality is that the whole procedure of calculating total depth is mathematically very easy, but it offers no information on the cut-quality, and as such, it is of no use.

Unfortunately, many people in the trade are so used at working with this figure, simply because it used to be one of the only two numbers on a GIA-report, but it means nothing.

Like you say, by calculating depth as a percentage of the smallest diameter, there is no standard basis to work with. The longer your length, the deeper your depth-percentage.

I have written various articles in the Pricescope Journal, mainly on depth in princess-cuts, but much also applies to other fancy shapes.

For instance, cutters of many proprietary cuts have the total depth calculated in a different way. Very often, they calculate the percentage with the longest diameter (from point to point) as the basis, which greatly reduces the depth-percentage. Many people are confused by this, and think that a lower depth means a higher spread.

Also, too many people, in and outside of the trade, are comparing the depth of rounds (around 60%) with the depth of fancy shapes, not realising that the calculation is not the same. Rounds'' depth-percentage is a percentage of the average diameter, in fancy shapes, it is a percentage of the smallest diameter. Big difference.

All in all, this is a very sad situation, I think.

Live long,

Yes..., I remember reading your writing (dont remember if it was an article or post) in regards to Princess cut depth calculations..., if I remember correctly you said the corners should be taken into consideration when calculating total depth..., and I agreed with you partly..., and here is why...:

A sharp cornered square princess cut or SMB (let say 5.6x5.6mm in diameter) would have a point to point measurement of approx. 7.92mm.
While a cut cornered square modified brilliant (a type of Radiant cut) with the same diameter would have a corner break to corner break measurement of approx. 6.4mm.

Big difference!!! But I do think there should be some kind of common ground for consideration when calculating fancy shaped Diamond''s total depth %.

There is no doubt in my mind that the current measurement formula used by ALL laboratories should be modified together with all the changes going on when grading or measuring different parts of the Diamonds.

I hope some more experts are going to chime in..., and maybe the big ears will hear the simple common sense behind this

 

[Garry H (Cut Nut)]

DG one reason is that even for small rounds the girdle thickness in % should always be much higher to avoid chipping.

At this page http://www.adamasgem.org/cut.html#girdleMarty Haske explains how GIA measure girdle thickness - it is an estimate of mm thickness, not % as AGS and some other labs use.

this time GIA has it right.
A 0.10ct diamond should have an very thick gidle if you want to use %

 

[diagem]

Date: 11/8/2007 7:26:01 AM
Author: Garry H (Cut Nut)
DG one reason is that even for small rounds the girdle thickness in % should always be much higher to avoid chipping.

Makes sense..., and no problem with that.

At this page http://www.adamasgem.org/cut.html#girdleMarty Haske explains how GIA measure girdle thickness - it is an estimate of mm thickness, not % as AGS and some other labs use.

this time GIA has it right.
A 0.10ct diamond should have an very thick gidle if you want to use %

But let me ask you..., what would be the TD% of an Ideal or Ex cut RB of (let say) 1.5-3.0 mm. diameter?

 

[oldminer]

Coining a new term:

Depth percentage for fancy shapes is something easy to calculate, but pretty much meaningless as the diamond gets longer. You are right. I think it became a popular gauge of cut quality mostly because it was a number we could easily obtain and had some meaning for rounds and square cuts.
Depth percent does not take a bulging pavilion shape into account or the length of fancy shapes.

I'd prefer to see the average depth percent for all diamonds used instead if we are going to make this calculation and say it has some small meaning. It still does not take outline or other features into account. In essence, it would remain a very rough filter for stone searching at best.

My preference would be a measure of the visible, face-up surface area within the border of the girdle outline compared to weight and adjusted to 1 carat. This would serve to provide consumers with a means to properly determine which diamond(s) have more visible size than others of similar weight range. It could assist them in shopping better than depth percent as it exists now or even if it was made as an average.

Here is an example of what I'd propose:

a 6 x 6 x 4.2mm princess cut has a visible surface of 36 square mm. It would weigh about 1.25ct.

divide 36 by 1.25 to equal 28.8mm per carat. an efficiency of 28.8

compare this to another princess cut measuring 5.8 x 6.2 x 4.06m with a visible surface area of 35.96 square mm. The weight estimate would be 1.21ct.

divide 35.96 by 1.21 to equal 29.7mm per carat an efficiency of 29.7

If, however, the above princess cut weight was 1.30ct because of a heavy girdle or a bulging pavilion, etc, then the result would be: 35.96 divided by 1.30 to equal 27.66 per carat
an efficiency of 27.66

What does this show?
It shows that although the visible surface area is virtually identical, that the "efficiency" is higher on the slightly rectangular stone at a lower weight and is less "efficient" when the weight is higher.

I'd like the trade to accept the word "Efficiency" and this methodology of calculating it for all diamonds, regardless of shape. It would replace any meaning or measure now referred to as depth percentage. Paul, Dia-Gem, Garry, and all, do you see this as something workable and meaningful? I believe this would one of those tools which would help consumers to compare diamonds before seeing them in person or to compare similar weight diamonds regardless of shape; a partial fix to comparing apples to oranges.

 

[diagem]

Date: 11/8/2007 8:27:36 AM
Author: oldminer
Coining a new term:

Depth percentage for fancy shapes is something easy to calculate, but pretty much meaningless as the diamond gets longer. You are right. I think it became a popular gauge of cut quality mostly because it was a number we could easily obtain and had some meaning for rounds and square cuts.
Depth percent does not take a bulging pavilion shape into account or the length of fancy shapes.

I''d prefer to see the average depth percent for all diamonds used instead if we are going to make this calculation and say it has some small meaning. It still does not take outline or other features into account. In essence, it would remain a very rough filter for stone searching at best.

I am with you on this..., but how would you average the calculation on some wacky shapes? we are going to need a consensus.

My preference would be a measure of the visible, face-up surface area within the border of the girdle outline compared to weight and adjusted to 1 carat. This would serve to provide consumers with a means to properly determine which diamond(s) have more visible size than others of similar weight range. It could assist them in shopping better than depth percent as it exists now or even if it was made as an average.

Only one problem..., I think there is more to a Diamonds beauty than its two dimension "visible size"..., I think a Diamonds beauty should be measured in a three dimensional model..., for example some Diamonds (like Asschers/ emeralds/ cushions, etc...etc..) enjoy a high crown height or what I call "sculpture effect" which cant be measured in a two dimensional model...,
We need to take this into consideration as well!



Here is an example of what I''d propose:

a 6 x 6 x 4.2mm princess cut has a visible surface of 36 square mm. It would weigh about 1.25ct.

divide 36 by 1.25 to equal 28.8mm per carat. an efficiency of 28.8

compare this to another princess cut measuring 5.8 x 6.2 x 4.06m with a visible surface area of 35.96 square mm. The weight estimate would be 1.21ct.

divide 35.96 by 1.21 to equal 29.7mm per carat an efficiency of 29.7

If, however, the above princess cut weight was 1.30ct because of a heavy girdle or a bulging pavilion, etc, then the result would be: 35.96 divided by 1.30 to equal 27.66 per carat
an efficiency of 27.66

What does this show?
It shows that although the visible surface area is virtually identical, that the ''efficiency'' is higher on the slightly rectangular stone at a lower weight and is less ''efficient'' when the weight is higher.

I''d like the trade to accept the word ''Efficiency'' and this methodology of calculating it for all diamonds, regardless of shape. It would replace any meaning or measure now referred to as depth percentage. Paul, Dia-Gem, Garry, and all, do you see this as something workable and meaningful? I believe this would one of those tools which would help consumers to compare diamonds before seeing them in person or to compare similar weight diamonds regardless of shape; a partial fix to comparing apples to oranges.

Dave..., how would you translate "efficiency" to "beauty"..., after all..., a Diamond is first of all beautiful!!! Only then it becomes efficient/scientific!

I like your thinking though..., I think this issue needs to be addressed seriously..., and am willing to participate in a brainstorm session with you and any other experts on this forum or off!

Hope to get more feed-backs from experts who believe as we do that this subject needs addressing.

 

[oldminer]

Beautiful is a subjective thing. To the trained art connoisseur a Picasso has great artistic merit and substantial beauty. To another observer, it might look like the work of a crazy person or an amateur. The work of many other respected and famous artists is much the same.

I would say that "efficiency" relates better to the concept of "highest and best use" which is an appraiser''s term for getting the most bang for your buck, in layman''s terms. The diamond industry strives mightily with the economic reality of obtaining the best possible return on rough diamonds within an ever narrowing range of profitability. In doing this, the cutter must also make a best effort at creating a beautiful outcome. Diamond, by its high luster and special properties allows itself to be cut only within certain configurations to get standardized shapes and appearances. I have yet to see one of the laser cut animals or letters of the alphabet cut in a diamond that looked better than passable, let alone beautiful.

It is my opinion that depth percentage relays little useful information except with round and possibly squarish stones. Even average depth percentage, while more fair in approaching all shapes with the same formula relays very little hard data of more than slight value for rough screening. However, an Efficiency measure as described could give people a meaningful comparison tools between similar weight diamonds of any set of shapes. You could make some meaningful comparison of a 1.50ct pear to a 1.52ct marquise, if you felt it necessary. You could say something intelligent about rectangular princess cuts as the bulge in a pavilion, avg. depth and/or girdle thickness would all be taken into account within a single result.

We can measure by counting pixels included within the girdle outline of any shape imaginable. Pixels have a known size and the correct sort of lens can give very defined edges adding a high degree of repeatability and accuracy to the measurement of square surface area. It is relatively easy to weigh a diamond with high accuracy, too. The end result would be highly repeatable, nearly an identifier of a particular diamond in many cases. Devices are already out there which could do a fairly good job with mounted diamonds and we can estimate weight pretty well with formulas. Appraisers could use this efficiency rating as an approximation without removing most diamonds from settings.

 

[Garry H (Cut Nut)]

Date: 11/8/2007 7:41:07 AM
Author: DiaGem

Date: 11/8/2007 7:26:01 AM
Author: Garry H (Cut Nut)
DG one reason is that even for small rounds the girdle thickness in % should always be much higher to avoid chipping.

Makes sense..., and no problem with that.

At this page http://www.adamasgem.org/cut.html#girdleMarty Haske explains how GIA measure girdle thickness - it is an estimate of mm thickness, not % as AGS and some other labs use.

this time GIA has it right.
A 0.10ct diamond should have an very thick gidle if you want to use %

But let me ask you..., what would be the TD% of an Ideal or Ex cut RB of (let say) 1.5-3.0 mm. diameter?

Here is a diamond of 1.5mm that has a GIA rule 0.15mm girdle that according to Marty would be graded as medium.
It has a depth % of 69.5%
A diamond of the same proportions at 1ct would measure 5.47mm and has a depth of 60.8%

I think a fair thickness on 1.5mm 60pc stone would be very thin and that has 64.5% depth.

(of course if it was an AGS rule stone the girdle would be a bit too thin at medium - it would then be 0.05mm)

Now DiaGem if you had DiamCalc too you would know all this stuff.

 

[Paul-Antwerp]

Hey Garry,

I am sorry, but are you having your traditional Friday-drink in the morning nowadays?

 

[Garry H (Cut Nut)]

Date: 11/8/2007 5:37:14 PM
Author: Paul-Antwerp
Hey Garry,

I am sorry, but are you having your traditional Friday-drink in the morning nowadays?

Ha ha, but I confess, i did have a couple of glasses of vino with my mussels at lunch, and we had Leffe at dinner last night with mussels again. We are taking the week off and in tasmania where the mussels are huge, so making the most of it.

But no - I have never had alcohol at breakfast, only cafe''

But pray tell - you were not aware of this little difference in lab grading rules Sir Paul (or is that Saint Paul?)

 

[stebbo]

Date: 11/8/2007 4:39:13 PM
Author: oldminer

It is my opinion that depth percentage relays little useful information except with round and possibly squarish stones. Even average depth percentage, while more fair in approaching all shapes with the same formula relays very little hard data of more than slight value for rough screening. However, an Efficiency measure as described could give people a meaningful comparison tools between similar weight diamonds of any set of shapes. You could make some meaningful comparison of a 1.50ct pear to a 1.52ct marquise, if you felt it necessary. You could say something intelligent about rectangular princess cuts as the bulge in a pavilion, avg. depth and/or girdle thickness would all be taken into account within a single result.

We can measure by counting pixels included within the girdle outline of any shape imaginable. Pixels have a known size and the correct sort of lens can give very defined edges adding a high degree of repeatability and accuracy to the measurement of square surface area. It is relatively easy to weigh a diamond with high accuracy, too. The end result would be highly repeatable, nearly an identifier of a particular diamond in many cases. Devices are already out there which could do a fairly good job with mounted diamonds and we can estimate weight pretty well with formulas. Appraisers could use this efficiency rating as an approximation without removing most diamonds from settings.

A few things come to mind, mostly to do with face-up area being used:

1. A 1ct round and 1ct princess, both bullseye AGS-0's, will have different face-up areas just by the nature of their optimized 3d shape. Consumers will get caught up in single numeric like efficiency and possibly shy away from princesses and other less weight-efficient shapes.

2. Even with equal face-up areas, a 36mm2 square appears smaller than a 36mm2 circle. This and the previous point would necessitate some equalizing treatment or normalization between shapes, or alternatively efficiency could become relative to a tolk-like standard in each shape.

3. A special camera setup would be required to take a photo exactly head-on, and scaling would have to be consistent scaling across all shapes and sizes. Amongst other things, this means maintaining a constant distance between camera and the perimeter of interest (ie. upper girdle edge). An orthographic projection of a scan would be less hassle.

4. Is it fair that the small diamond Garry talks about be penalized for its appropriate girdle?

5. In the perception of size, face-up area ignores both optical spread and 3d 'plumpiness' (I call it the beer-belly effect). In the extreme, looking side on, it's now all about vertical spread. Practically it's a dynamic mix.

 

[Paul-Antwerp]

Date: 11/8/2007 11:27:17 PM
Author: stebbo

2. Even with equal face-up areas, a 36mm2 square appears smaller than a 36mm2 circle. This and the previous point would necessitate some equalizing treatment or normalization between shapes, or alternatively efficiency could become relative to a tolk-like standard in each shape.

I beg to disagree with this.

Your remark is probably correct, when talking about comparing the two shapes on paper, but with real life stones, we can work with light return, and if we do that intelligently, we can change that perception.

Do you remember the set of two round stones, that Garry constantly carries around, where the one with the smallest surface area looks bigger. this is because of edge-to-edge light return.

In the same way, in a princess-cut, if we make sure to stress the long diameter from point to point (almost 8mm in a 1Ct), to many observers this princess will seem bigger than the 1Ct-round. Although it has a much smaller surface area. So, when we are talking about the same surface-area, I think that the good square always wins.

This is of course not true for all princess-cuts. You have to take care to plan that strong brightness from point-to-point. In an ASET-scope, it is clear when you have an uninterrupted area of red from corner-to-corner. Most princess-cuts do not have that, not even all AGS-0''s. But it is a very important distinctive factor, which make these stones stand out amongst their peers.

To summarize: you are most probably right n most cases, but if we work intelligently as cutters, we are capable of proving your remark wrong.

Live long,

 

[Garry H (Cut Nut)]

Date: 11/9/2007 2:03:44 AM
Author: Paul-Antwerp
I beg to disagree with this.

if we work intelligently as cutters, we are capable of proving your remark wrong.

Live long,

oho - I could get into to trouble

 

[stebbo]

Date: 11/9/2007 2:03:44 AM
Author: Paul-Antwerp
I beg to disagree with this.


Your remark is probably correct, when talking about comparing the two shapes on paper, but with real life stones, we can work with light return, and if we do that intelligently, we can change that perception.

In the same way, in a princess-cut, if we make sure to stress the long diameter from point to point (almost 8mm in a 1Ct), to many observers this princess will seem bigger than the 1Ct-round. Although it has a much smaller surface area. So, when we are talking about the same surface-area, I think that the good square always wins.


This is of course not true for all princess-cuts. You have to take care to plan that strong brightness from point-to-point. In an ASET-scope, it is clear when you have an uninterrupted area of red from corner-to-corner. Most princess-cuts do not have that, not even all AGS-0''s. But it is a very important distinctive factor, which make these stones stand out amongst their peers.


To summarize: you are most probably right n most cases, but if we work intelligently as cutters, we are capable of proving your remark wrong.


Live long,

Lots of potential there, I agree--in fact it reminds me of the samurai warrior who took his first plane trip and was told his meter long sword was longer than the 80cm maximum allowed. Know what he did?....

He bought a 60x80cm case and laid it across the diagonal.

But related to Dave''s efficiency rating where optical effects are ignored, all that work would go unrewarded.

 

[oldminer]

The work which goes into creating beauty is rewarded with a measure(s) of light behavior. The Efficiency rating goes into another measure which I presently call DFS; Durability, Finish and Size. Efficency would take over the current use of the depth percent as the Size component. Labs should give a Light Behavior Grade and accompany it with a Craftsmanship grade, not combine the two. That''s my opinion, currently a minority one. I''m sticking to it with my usual dose of optimism.

 

[Paul-Antwerp]

Date: 11/9/2007 7:05:36 AM
Author: oldminer
The work which goes into creating beauty is rewarded with a measure(s) of light behavior. The Efficiency rating goes into another measure which I presently call DFS; Durability, Finish and Size. Efficency would take over the current use of the depth percent as the Size component. Labs should give a Light Behavior Grade and accompany it with a Craftsmanship grade, not combine the two. That''s my opinion, currently a minority one. I''m sticking to it with my usual dose of optimism.

The effect, that I am refering to, is not separately graded by AGS, since it is missed in the quantification of the ASET-model and the Fire-model.

In the same way, I cannot see any model or machine capable of quantifying such optical effects. This effect is observable, but missed both in your proposed efficiency-rating, as in any lab''s of machine''s light behavior-system.

Live long,

 

[diagem]

style="WIDTH: 97.61%; HEIGHT: 265px">Date: 11/8/2007 4:39:13 PM
Author: oldminer
Beautiful is a subjective thing. To the trained art connoisseur a Picasso has great artistic merit and substantial beauty. To another observer, it might look like the work of a crazy person or an amateur. The work of many other respected and famous artists is much the same.

True..., but a Diamonds beauty is still a huge part of the equation..., The works of art you are mentioning can be compared more towards jewelry pieces/design in my opinion.

I would say that ''efficiency'' relates better to the concept of ''highest and best use'' which is an appraiser''s term for getting the most bang for your buck, in layman''s terms. The diamond industry strives mightily with the economic reality of obtaining the best possible return on rough diamonds within an ever narrowing range of profitability. In doing this, the cutter must also make a best effort at creating a beautiful outcome. Diamond, by its high luster and special properties allows itself to be cut only within certain configurations to get standardized shapes and appearances. I have yet to see one of the laser cut animals or letters of the alphabet cut in a diamond that looked better than passable, let alone beautiful.

It''s true that a cutter has to make the best effort in creating a beautiful outcome..., but your aiming to "standardized shapes and appearances".
I think the future of Diamond cutting will look different that today''s "laser cut animals and letters", etc..., etc..., innovation is and will be key and thats where "I personally" feel the future Diamond cutting is heading! When calculating ''efficiency'' for future potential cutting techniques..., we are going to have to take into consideration more than just the "highest and best use" or as a matter of fact the slogan "most bang for your buck".

It is my opinion that depth percentage relays little useful information except with round and possibly squarish stones. Even average depth percentage, while more fair in approaching all shapes with the same formula relays very little hard data of more than slight value for rough screening. However, an Efficiency measure as described could give people a meaningful comparison tools between similar weight diamonds of any set of shapes. You could make some meaningful comparison of a 1.50ct pear to a 1.52ct marquise, if you felt it necessary. You could say something intelligent about rectangular princess cuts as the bulge in a pavilion, avg. depth and/or girdle thickness would all be taken into account within a single result.

I agree with you that depth % has little useful info., but we have created a creature..., the consumer is becoming more educated by information we (industry members and others) forward or teach them..., A diamond today comes attached with a paper (lab. report)..., either the #''s are within the range or not..., for example..., I have read in plenty of places (incl. PS, but not only...) that an RB which is NOT within the "ideal--EX range" is considered a "dog"

, that I think is a bit exaggerated, no???

We can measure by counting pixels included within the girdle outline of any shape imaginable. Pixels have a known size and the correct sort of lens can give very defined edges adding a high degree of repeatability and accuracy to the measurement of square surface area. It is relatively easy to weigh a diamond with high accuracy, too. The end result would be highly repeatable, nearly an identifier of a particular diamond in many cases. Devices are already out there which could do a fairly good job with mounted diamonds and we can estimate weight pretty well with formulas. Appraisers could use this efficiency rating as an approximation without removing most diamonds from settings.

Dave..., it sounds like another useful information element..., but it has to be adjusted to specifics.
With today''s technological tooling''s, a sq. mm. surface measurement needs to be adjusted and combined to other elements as for example the appearance of the Diamond in subject.
Not all Diamonds are cut to maximize brilliance (if I am not mistaken..., you''ve mentioned it in a past thread

)

Take for example a Princess cut Diamond..., a one carat can be a beautiful ideally cut 5.5x5.5 mm at approx. 76% TD. (incl. more specifics..., Does 76% still earn the ideal diploma??

)
But again..., if cut correctly, it could also be a beautiful 6.3x6.3mm at approx. 50% TD. (am I right Paul?)

If we want to come up with a new type of measuring device for surface area..., we are going to need to use technology to help adjust/ adapt measurements to specific shapes and appearances.

(My opinion) measuring a two dimensional model just wouldnt do it in todays technological era...

 

[diagem]

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)

Now DiaGem if you had DiamCalc too you would know all this stuff.

And give up my communication relationship with you...?

I dont think so!!!

BTW..., (for argument sake)..., let say we submit a 1.5 mm BR with 69.5%TD to AGS or GIA..., what cut-grade will it earn???

 

[diagem]

Date: 11/9/2007 7:23:27 AM
Author: Paul-Antwerp

Date: 11/9/2007 7:05:36 AM
Author: oldminer
The work which goes into creating beauty is rewarded with a measure(s) of light behavior. The Efficiency rating goes into another measure which I presently call DFS; Durability, Finish and Size. Efficency would take over the current use of the depth percent as the Size component. Labs should give a Light Behavior Grade and accompany it with a Craftsmanship grade, not combine the two. That''s my opinion, currently a minority one. I''m sticking to it with my usual dose of optimism.

The effect, that I am refering to, is not separately graded by AGS, since it is missed in the quantification of the ASET-model and the Fire-model.

In the same way, I cannot see any model or machine capable of quantifying such optical effects. This effect is observable, but missed both in your proposed efficiency-rating, as in any lab''s of machine''s light behavior-system.

Live long,

I fully agree with Paul...

"Light behavior grade" will still be graded by humans???
What about Diamonds that dont need a reward for optimized light behaviour??? Like Briolettes for example? (one example of many...)

A new type of measuring device/machine will need to take a lot more into consideration

 

[oldminer]

DiaGem, I think you have hiot on an important topic. Diamonds which are cut for their shape, not for light return, such as briolettes, rose cuts, baguettes. We stress symmetry, outline and polish for those and anymeasure of light behavior would be relegated to how well two or a set match eachother. You know a good briolette from a poor one. A lumpy, misshapen one is not as nice to look at or as valuable as a symmetry, shaped one. Craftsmanship dictates a good part of the quality is such cases.

When I say "standard shapes", I mean those which the trade and the consumer agree upon which will sell and not sit in a dealer''s inventory. I don''t mean to imply any preconceived notion about limiting shapes or discovering new things which appeal to both the trade and consumers.
However, once a shape meets with success, more people will want to quantify and compare it. The we need tools which do the process as it is a waste of human resources to do what machiones can do tirelessly, with far less subjectivity, and with tiny amounts of anticipated error.

Currently, the two most popular shapes, round and rectangular-square, can be easily measured for square mm area with high precision. With tools currently at my disposal, I can measure the square surface view area for any shape but I know most folks can''t do this today. No doubt, this will become more available in years to come.

 

[diagem]

Date: 11/9/2007 11:47:58 AM
Author: oldminer
DiaGem, I think you have hiot on an important topic. Diamonds which are cut for their shape, not for light return, such as briolettes, rose cuts, baguettes. We stress symmetry, outline and polish for those and anymeasure of light behavior would be relegated to how well two or a set match eachother. You know a good briolette from a poor one. A lumpy, misshapen one is not as nice to look at or as valuable as a symmetry, shaped one. Craftsmanship dictates a good part of the quality is such cases.

When I say 'standard shapes', I mean those which the trade and the consumer agree upon which will sell and not sit in a dealer's inventory. I don't mean to imply any preconceived notion about limiting shapes or discovering new things which appeal to both the trade and consumers.
However, once a shape meets with success, more people will want to quantify and compare it. The we need tools which do the process as it is a waste of human resources to do what machiones can do tirelessly, with far less subjectivity, and with tiny amounts of anticipated error.

Currently, the two most popular shapes, round and rectangular-square, can be easily measured for square mm area with high precision. With tools currently at my disposal, I can measure the square surface view area for any shape but I know most folks can't do this today. No doubt, this will become more available in years to come.

you are making sense...
But unfortunately..., most are still looking and comparing the #'s listed on the reports..., so as far as my example on the two Princess cuts mentioned previously... (a popular shape...)

One Princess cut 5.5x5.5mm. and one 6.3x6.3mm in diameter...,both properly cut, both one carat in weight..., both beautiful...
How would you translate the surface area to a consumer? The shallow one is better value as it has a significant larger surface and probably less expensive
(as it falls from the ideal range) vs. the ideal cut Princess which has a smaller surface area but is ideally cut and so is more expensive?

Or the opposite?

 

[Garry H (Cut Nut)]

Date: 11/9/2007 9:23:03 AM
Author: DiaGem

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)

Now DiaGem if you had DiamCalc too you would know all this stuff.

And give up my communication relationship with you...?

I dont think so!!!

BTW..., (for argument sake)..., let say we submit a 1.5 mm BR with 69.5%TD to AGS or GIA..., what cut-grade will it earn???

Neither will grade stones that small.
But if GIA did it would ding the stone for exceeding maximum depth %. Or if the girdle was thin enough to pass that hurdle they would ding it for being too thin

AGS would pass the stone with 3% girdle - but if the girdle was practicall thickness they would ding it for being over -5% spread (ie too small a diameter compared to 1ct = 6.47mm).

Both systems work for the sizes they are designed for.

 

[stebbo]

Date: 11/9/2007 11:52:34 PM
Author: Garry H (Cut Nut)

Neither will grade stones that small.

But if GIA did it would ding the stone for exceeding maximum depth %. Or if the girdle was thin enough to pass that hurdle they would ding it for being too thin

Apparently GIA don''t grade big stones either:

 

[diagem]

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)


Now DiaGem if you had DiamCalc too you would know all this stuff.

Garry..., a (humble) question for ya...

Why should I get a DiamCalc/Octo and not Sarin?

I understood Sarin''s CGA is almost the same? Or was I informed wrongly?

 

[Garry H (Cut Nut)]

Date: 11/11/2007 4:38:58 AM
Author: DiaGem

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)


Now DiaGem if you had DiamCalc too you would know all this stuff.

Garry..., a (humble) question for ya...

Why should I get a DiamCalc/Octo and not Sarin?

I understood Sarin''s CGA is almost the same? Or was I informed wrongly?

DiamCalc is a $395 software product. Sarin have nothing like it (other than a $500 realistic viewer that is a dumbed down version of DiamCalc that OctoNus supply under licence to Sarin).

But OctoNus make scanners called Helium Polished and Helium Rough. Sarin could tell you there are similarities. but.............

 

[diagem]

Date: 11/11/2007 5:43:38 AM
Author: Garry H (Cut Nut)

Date: 11/11/2007 4:38:58 AM
Author: DiaGem

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)


Now DiaGem if you had DiamCalc too you would know all this stuff.

Garry..., a (humble) question for ya...

Why should I get a DiamCalc/Octo and not Sarin?

I understood Sarin''s CGA is almost the same? Or was I informed wrongly?

DiamCalc is a $395 software product. Sarin have nothing like it (other than a $500 realistic viewer that is a dumbed down version of DiamCalc that OctoNus supply under licence to Sarin).

But OctoNus make scanners called Helium Polished and Helium Rough. Sarin could tell you there are similarities. but.............

What is the $3,900 product called DiamCalc I saw on their website?

 

[Garry H (Cut Nut)]

Date: 11/11/2007 7:12:25 AM
Author: DiaGem

Date: 11/11/2007 5:43:38 AM
Author: Garry H (Cut Nut)

Date: 11/11/2007 4:38:58 AM
Author: DiaGem

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)


Now DiaGem if you had DiamCalc too you would know all this stuff.

Garry..., a (humble) question for ya...

Why should I get a DiamCalc/Octo and not Sarin?

I understood Sarin''s CGA is almost the same? Or was I informed wrongly?

DiamCalc is a $395 software product. Sarin have nothing like it (other than a $500 realistic viewer that is a dumbed down version of DiamCalc that OctoNus supply under licence to Sarin).

But OctoNus make scanners called Helium Polished and Helium Rough. Sarin could tell you there are similarities. but.............

What is the $3,900 product called DiamCalc I saw on their website?

The version you get after you learn to drive the $395 model

 

[diagem]

Date: 11/11/2007 1:41:16 PM
Author: Garry H (Cut Nut)

Date: 11/11/2007 7:12:25 AM
Author: DiaGem

Date: 11/11/2007 5:43:38 AM
Author: Garry H (Cut Nut)

Date: 11/11/2007 4:38:58 AM
Author: DiaGem

Date: 11/8/2007 5:04:55 PM
Author: Garry H (Cut Nut)


Now DiaGem if you had DiamCalc too you would know all this stuff.

Garry..., a (humble) question for ya...

Why should I get a DiamCalc/Octo and not Sarin?

I understood Sarin''s CGA is almost the same? Or was I informed wrongly?

DiamCalc is a $395 software product. Sarin have nothing like it (other than a $500 realistic viewer that is a dumbed down version of DiamCalc that OctoNus supply under licence to Sarin).

But OctoNus make scanners called Helium Polished and Helium Rough. Sarin could tell you there are similarities. but.............

What is the $3,900 product called DiamCalc I saw on their website?

The version you get after you learn to drive the $395 model

I might be interested if I can try-out and will be able to visualize appearances of new or odd Diamond designs...
Is there a link to your direct email on your web-site? (I hope its OK asking here

)

 

[Garry H (Cut Nut)]

You can get me from that website or many others DG