Are Radiant Cuts properly evaluated on Pricescope?

[Rockdiamond]

thanks all!
ffs- thanks for posting that Aset, and ORC parameters!
Regarding the aset: I would not call that red "uniform" at all.
The red areas at the edge shown are some of the weakest potential points in the execution of the design. Basically they show areas that will be dark in comparison to the greens and white parts which will be bright. On good examples ( and this is probably one) slight tilt lights up the areas depicted in red on the ASET.

A bit about brands, and how they relate to this discussion.
Regarding Original Radiant Cuts: The basis of that particular brand is quite different than most other diamond brands.
The reasons have to do with the versatility of the basic concept, and implementation.
Using AVC, or DBL's Branded Cut for Color Antique style stones as a comparison of differences between brands will be illustrative.
I don't see that others will copy either ours, or the AVC design- for a number of reasons. A patent, or legal reasons will not prevent anyone from trying to copy either design.
What protects these designs are the seller's reputations- and the skill involved in getting those particular results.
Possibly more pressing today is incredible difficulty in obtaining rough.

Henry originally tried to protect his design- but quickly learned that it was going to end up being "open source"
The resultant shared technology means that there's a lot of well cut stones on the market we can use to demonstrate the look I'm talking about.

I will indeed ask Stan for a few stones to use as models- but I'll also find some generic cushions and radiant cuts with the characteristics I'm talking about.

 

[Garry H (Cut Nut)]

Thanks JulieN-
Redrocket- my goal is to create a better context for shoppers that takes into account the different types of Modified Brilliant Diamonds- that is how a Radiant Cut is categorized by GIA.
Your confusion is by no means uncommon- no need to feel like you're missing something.
There's scant information available on Modified Brilliant stones.

Hi Yoram- Happy New Years!
I think everyone would agree that the sales pitch you quoted was nowhere near education.
I'm not clear as to how that relates to this subject.


The break point on the pavilion, means that the facets lines that form the culet do not touch the girdle.
This is the "modified" aspect of a "Cut Cornered Rectangular Modified Brilliant".
Part of the reason people here are critical of the cut is that it allows a lot of funny stuff. This is a valid concern.

But unlike a stone cut to "Brilliant", the modified aspect allows for a really wide range of possibilities.
Some can be cut to the same standards of symmetry and polish as a non modified.

For the purposes of discussion, let's consider Radiant Cuts that are cut for color.
This really gives cutters a licence to utilize the rough with far less constraint about symmetry. The plot example above- randomly chosen- illustrates extra facets on the pavilion. If perfect symmetry is the goal, then it's a problem. But what if that extra facet has an imperceptible affect on the overall optics of the diamond?
Sometimes it might be a budging pavilion, effectively hiding 10% of the weight.
But other times it might mean utilizing piece of rough of a desirable shape differently in ways related to optics, as opposed to weight retention primarily.

Cutters today are handcuffed to the Rap Sheet.
They have to cut rounds.
It's getting harder and harder to find colorless fancy shapes

My point is- sometimes a cutter can utilize the freedom associated with the modified design to do something different, and extraordinary.
Which I've seen you do many times Yoram.
But others do it differently.

What does everyone think of patterns of green and white in an ASET of a Radiant?

Sorry I am very late to this great party.
A couple of quick comments, but note I have not read all and have little time today.
1. David those extra facets are probably scan errors, especially the big on on the lower girdle facet.
2. If you want to experiment with CZ, then DiamCalc can be used because you can change from CZ to diamond and then make adjustments to depth and crown height to get the closest approximation in ASET and other visual effects.

 

[Rockdiamond]

HI Garry!
In terms of testing using CZ's and DiamCalc- interesting concept- I actually think it relates to the first comment, about the scan error and extra facet.
Here's a photo of the diamond from the GIA plot- it's in a setting that won't allow me to see the facet in question- but there's no reason for me to believe that there is not an extra facet there. I believe I an actually see the extra facet in this photo- but in real life, the eye can not focus on a single facet that way due to the additional light bounces.

There's plenty of reasons such a facet might contribute to the overall feasibility of a given design, and a given piece of rough.
It can be directly or indirectly related to weight retention.

As ffs mentioned- fancy colors provide a great platform to see what's possible.

We can agree that the RBC wins hands down on a brilliancy contests.
We can also agree not everyone wants an RBC- even if they're aware it's not the most brilliant, based on the standards developed to determine brilliancy.

These are the basic reasons fancy shapes exist.
If we release cutters from the tiny tolerances they are saddled with when cutting a round, all kinds of shapes, and different optical signatures become possible.

The nature of the way a radiant uses light means that some unlikely combos can actually look good.
For example, the table of the diamond in the photo is 77%.
We can all agree that we'd be extremely skeptical of a colorless diamond with a 77% table.
Most likely if it had been a colorless rough, it would have been a round diamond minus about 30% of it's current weight.
Since fancy colors require a different use of light- multiple bounces is a big plus, there' no choice here- with rough light yellow or darker, you go for the modified brilliant cushion, or radiant.
But I think that the fancy color stones show that these unusual combos can work well, if we're looking for stones utilizing light gathered from lower angles ( which is why we see green in the aset)

I think that discussions about weight retention- ie, cutters trying to save weigh, should also include insight into feasibility.
That is to say- if the optical goals are different, choices for the rough are different as well.

The result is that a well cut radiant may indeed utilize the rough more efficiently than a round. Which is another way of saying cut for weight retention.
This whole different way of looking at the rough means that a brand that is restricted by narrow expectations for appearance is handcuffed to the same type of restrictive standards as rounds.
I think the Original Radiant takes sensible approach to this entire discussion.
Looking at the available rough, and making the correct decisions.
Rectangular needs different considerations addressed as compared to square stones. Different sized corners

This all goes back to the suggestion of using CZ and DiamCalc

There's already so many variations of actual diamonds- which would make it seem that using actual diamonds is a better barometer if we're trying to advise consumers the best way to find well cut Modified Brilliant Stones.
If we're trying to design the ultimate diamond for a brand we need to call in Karl

 

[Garry H (Cut Nut)]

BTW David I am glad to see you have worked out how to use the ASET for fancy cuts and especially for these colored diamonds.
A tip - I noticed in several of your pic's that the hand that is holding the tweezers often shows up as a pink reflection - consider wearing a white or neutral coloured glove?

 

[Rockdiamond]

HI Garry,
Thanks- I have come to realize that it was shortsighted not to use the data. That was part of my problem.
A glove.....hmmm.
The problem is that you can never totally isolate the diamond from reflecting back the camera lens, among other things.
This is another aspect of ASET interpretation of Modified Brilliant Stones.
Since they're gathering light from lower angles things like a person's shirt will affect the light and color coming off the diamond.
So even if the glove is white, or neutral it will still affect the stone's optical signature photographically.
I'd have to find a glove from the "cloak of invisibility"

Hi ffs,
The stone I used is not an ORC- they don't cut fancy colored stones.
Here'a the plot showing extra facets.


Is it a well cut stone?
Exceptionally so for a Fancy Colored Radiant IMO.
Interesting how you can draw such pointed conclusions about fire, brilliance and saturation from two photos, taken by different cameras and photographers.
I always advise consumers to look at multiple photos- and to try and get ones that are clearly not glamour shots.


With regard to ASET of Fancy Colored Diamonds: I do not believe the body color prevents use of ASET. The distinct difference from green to red to blue is still visible even if it's tinted.
Furthermore, although it's been suggested to use DiamCalc, that is one area where I am less willing to change my methodology.
Looking at computer generated models is certainly useful for some aspects of diamond cutting, or assessment.
I prefer to focus my time on real diamonds.

 

[Rockdiamond]

None of those photos is acceptable in this type of discussion.
Two aspects are problematic
1) with the additional light bounces, where should we focus the camera- the skin or inside? None of those are properly focused
2) tilt - no one of those photos is close enough to straight on to give a good idea

 

[denverappraiser]

David,

At the risk of suggesting you need to work harder, the only way to do this is for you to take the pictures and the ASET images yourself in a standardized sort of what so that you know that they were all done the same and that the differences you see are about the stones. It also needs to be stones that YOU can physically inspect and give an independent eye-based evaluation of what's good, bad, crappy or whatever. Armed with that you can then see if there are features in the images that correlate with the stones you like (or disike). That gives a baseline to work from. Without that we're on the same path you've been objecting to for years.

 

[CharmyPoo]

David - you should then provide better examples of photos since you likely have more acccess to these diamonds than the rest of us.

 

[Rockdiamond]

I agree Neil
I have been putting a lot of thought into the best way to move this forward.
I need to find candidates that meet certain specifications regarding light return and optics. Thank you as well Charmy- I do believe I have some stones that will work
I've also been using this very discussion and the ideas introduced to formulate methodology.

As I mentioned there are aspects of the modified brilliant design that complicate photography.
I think Neil has a good point about standardized photos.
I plan to use a lightbox for this to try and achieve more consistency

I hope to start with photos and aset of a few stones tomorrow

 

[Garry H (Cut Nut)]

David is this to be for fancy colors or colorless stones?
The rules and goals are in my opinion very different.

 

[Rockdiamond]

What a great question Garry- it goes right to the heart of it
Do diamonds cut for color provide good examples for diamonds in general
Are there enough shared goals?
I think they do

 

[Garry H (Cut Nut)]

What a great question Garry- it goes right to the heart of it
Do diamonds cut for color provide good examples for diamonds in general
Are there enough shared goals?
I think they do

I think we have very different points of view then David.
Fancy colored diamonds are mostly cut from pale material with a desire to make the color more intense, but not darken the tone.
So the goal is to reduce the contrast, like that caused by rays that go straight in the top and straight out again. But in colourless diam0onds that contrast is very important in creating the perception of brightness (a moving chess board is brighter than a sheet of white paper.
No contrast = no scintillation.
In colourless diamonds we want that pinfire rolling scintilation that comes from the colour flashing against the usually nothing color of the leakage.
Totally different goals.

 

[Rockdiamond]

Hi Garry- I think the fact we have differing opinions is eminently clear. Of course this type of discussion is very enlightening- and please don't mistake my having a different opinion as any sort of knock on your ideas.
I'd like to find ways of defining what I see and love in fancy shapes using reflector technology- so your assistance is greatly appreciated.

I would not say its a fair generalization that "most" fancy colored diamonds are cut from pale rough. There's many deeper brown stones- or even Intense or vivid yellow.
But I do agree that a lot of lighter fancy colors are indeed cut from a more pale rough- and further that there's methods cutters use for bringing out this color. Furthermore, I've had discussions with some great cutters that feel like these cutters are "cheating" BUT- I've also had a lot of discussions with other, really great cutters who do not see it as cheating- and in fact have developed methods of utilizing shallow rough ( both in terms of color, ad well as physical depth) to produce lovely, spready stones- that consumers love.

I agree that longer light paths are the goal in fancy colored diamond cutting- but the opportunity to relate this difference in philosophy to how we look at fancy shapes is part of the discussion, in my mind.
This goes back to a discussion of what we're looking for in the stone.
If we're looking for perceived brilliance, as it's measured in a round, we need to find fancy shaped stones that follow the round brilliant model and philosophy.
Correct me if I'm wrong Garry, but for this type of brilliance, we'd be looking for a lot of large red blocks in the aset.

My feeling is that the Radiant Cut, as envisioned by Henry Grossbard- then subsequently improved and refined over the years is aiming for different goals- which are more closely related to the way a fancy colored diamond uses the light.
Therefore the aset will feature much smaller blocks of color- with a prevalence of green and white.

 

[Garry H (Cut Nut)]

I would not say its a fair generalization that "most" fancy colored diamonds are cut from pale rough. There's many deeper brown stones- or even Intense or vivid yellow.
But I do agree that a lot of lighter fancy colors are indeed cut from a more pale rough- and further that there's methods cutters use for bringing out this color. Furthermore, I've had discussions with some great cutters that feel like these cutters are "cheating" BUT- I've also had a lot of discussions with other, really great cutters who do not see it as cheating- and in fact have developed methods of utilizing shallow rough ( both in terms of color, ad well as physical depth) to produce lovely, spready stones- that consumers love.

I agree that longer light paths are the goal in fancy colored diamond cutting- but the opportunity to relate this difference in philosophy to how we look at fancy shapes is part of the discussion, in my mind.
This goes back to a discussion of what we're looking for in the stone.
If we're looking for perceived brilliance, as it's measured in a round, we need to find fancy shaped stones that follow the round brilliant model and philosophy.

I removed some parts for a seperate discussion David.
We agree. But please read below and I will share the why:
I would really like you to open this page http://www.octonus.com/oct/projects/fancycolor-5.phtml
The graph describes the boundaries of the Fancy Yellow grades. There are various color samples of diamonds and the numbers in millimeters describe what happens to grades (i.e. colors) with varying thickness.
So in the case of a brown stone (of course the grade system is for yellows so not 1000% appropriate) the thicker the slab of diamond the darker the stone gets. In the example of the Grey Brown you might want the thickness to be around 5mm to get the best result. So that means an average ray path across the stone should be under say 10mm. If the stone was 1/2ct then cutting it to a suer ideal round brilliant will get the best result. Cutting a pinfire cushion or radiant would get a ray path of perhaps 3 times more and make the stone very dark and unsaleable.

With the same sized fancy yellow rough we are going to try to get that ray path up around 35mm, and if we can do this with little or no face up dark zones then where the Fancy Intense grade zone does a zig zag - we might get this piece of rough into the FIY zone. So while planning the cutting you would use the ASET modelling to make sure you remove as much blue as possible and have the most green and leakage across the stone. The blue = darkness, the red = generally shorter ray paths.
There is an advanced DiamCalc program that Sergey and Yuri designed for this purpose. DiaGem calls it cheating. Its certainly pushing the envelope.

 

[Rockdiamond]

Thanks Garry- isn't pushing the envelope what it's all about?
If we look at different methods of cutting Pear shapes and ovals, I've found some very attractive colorless ones cut more like a fancy colored pear. The facet design I'm thinking of creates a bounce pattern that completely eliminates the "bow tie" effect.
Generally four pavilion mains is part of the recipe.

 

[Garry H (Cut Nut)]

David will you promise me you will take the time to read the link please?

 

[Rockdiamond]

HI Garry,
I did read the page- although I'm not exactly sure what the relationship to this discussion is.
Part of the nature of cutting involves using the available rough to make the best stone possible. That's one reason the computed simulations are somewhat less relevant IMO.
The best cutters need to use the existing rough to make the best decisions. If we try to get a specific depth, table or other aspects, it makes purchasing the rough terribly difficult- and expensive.
I have found that using what nature gave us best has led imaginative cutters to design modified brilliant cuts that can be shallow, yet brilliant.

I remember having an incredible vivid yellow cushion once with a depth of 54.9%

My point is that a diamond's physical depth may not be directly related to the depth of color.

 

[Rockdiamond]

HI Garry, If possible can you please post the link to a video of your showing how to photograph an ASET?
I have not taken any aset photos in a while- I forgot the camera settings which you covered in your instructional video.


Here's what I've been pondering that past few days:
1) we can agree Round is the most brilliant
2) Fancy Shapes that are cut to mimic a round brilliant can be more easily judged using methods that work for a round

What this leaves us with is the need to develop new means to evaluate the cut of stones cut to different goals.
The next questions come from the fact that we are looking for different optical signatures- what should we be looking for?

One goal of a well cut modified brilliant is the type of look with a limited amount of tiny dark areas.
But we an also find some very nice modified stones that have patterning that will include some larger dark areas.
Is one better than the other?

Maybe "better" is not the operative word here.

 

[Garry H (Cut Nut)]

http://www.youtube.com/watch?v=6SfK5Nt3oXw
The same method works for ASET photo's - but you must use a point and click or a phone camera with a small lens.

David we do not need to develop a new method for pinfire or fancy color type cuts. You only need to read all the old posts. Its well known among many of the frequent posters.

 

[Rockdiamond]

Thanks for that link Garry- it was exactly the one I was looking for!

In terms of how many of the PS regulars generally approach this: When someone asks for help with a radiant they are first questioned to "make sure" that's what they want.
If it is, the next move is to have them look at one of the branded non pinfire radiant cuts.

I honestly can't remember a time when a person asking about a radiant cut is steered towards the original- or stones like it.

In terms of discussions of aset with green and white- I have not seen them- of course this does not mean they don't exist.
if anyone has a link, I'll look at the threads discussing the positive aspects of green and white in this type of stone.

 

[Garry H (Cut Nut)]

HI Garry,
I did read the page- although I'm not exactly sure what the relationship to this discussion is.
Part of the nature of cutting involves using the available rough to make the best stone possible. That's one reason the computed simulations are somewhat less relevant IMO.
The best cutters need to use the existing rough to make the best decisions. If we try to get a specific depth, table or other aspects, it makes purchasing the rough terribly difficult- and expensive.
I have found that using what nature gave us best has led imaginative cutters to design modified brilliant cuts that can be shallow, yet brilliant.

I remember having an incredible vivid yellow cushion once with a depth of 54.9%

My point is that a diamond's physical depth may not be directly related to the depth of color.

David the science can increase the ray length by adjusting facet positions etc AND achieving the best yield.

 

[diagem]

David the science can increase the ray length by adjusting facet positions etc AND achieving the best yield.

Garry, does the science also adjusts facet positions etc of standard 'colorless' facet structures?

 

[Rockdiamond]

HI Garry,
I did read the page- although I'm not exactly sure what the relationship to this discussion is.
Part of the nature of cutting involves using the available rough to make the best stone possible. That's one reason the computed simulations are somewhat less relevant IMO.
The best cutters need to use the existing rough to make the best decisions. If we try to get a specific depth, table or other aspects, it makes purchasing the rough terribly difficult- and expensive.
I have found that using what nature gave us best has led imaginative cutters to design modified brilliant cuts that can be shallow, yet brilliant.

I remember having an incredible vivid yellow cushion once with a depth of 54.9%

My point is that a diamond's physical depth may not be directly related to the depth of color.

David the science can increase the ray length by adjusting facet positions etc AND achieving the best yield.

There are specialists doing exactly that- AND lessening static dark areas.
But the point stands that a shallow stone may still have Vivid saturation.

 

[Garry H (Cut Nut)]

HI Garry,
I did read the page- although I'm not exactly sure what the relationship to this discussion is.
Part of the nature of cutting involves using the available rough to make the best stone possible. That's one reason the computed simulations are somewhat less relevant IMO.
The best cutters need to use the existing rough to make the best decisions. If we try to get a specific depth, table or other aspects, it makes purchasing the rough terribly difficult- and expensive.
I have found that using what nature gave us best has led imaginative cutters to design modified brilliant cuts that can be shallow, yet brilliant.

I remember having an incredible vivid yellow cushion once with a depth of 54.9%

My point is that a diamond's physical depth may not be directly related to the depth of color.

David the science can increase the ray length by adjusting facet positions etc AND achieving the best yield.

There are specialists doing exactly that- AND lessening static dark areas.
But the point stands that a shallow stone may still have Vivid saturation.

I never argued against that point David?

 

[Garry H (Cut Nut)]

David the science can increase the ray length by adjusting facet positions etc AND achieving the best yield.

Garry, does the science also adjusts facet positions etc of standard 'colorless' facet structures?

Different science David, the colored stones are usually planned stone by stone because they are often rather expensive.
With colorless when brilliance and fire are the goals there will be a best pattern and proportion set, and after that if the stone needs to be swindled then quality is sacraficed for yeild value.

Some time ago our little Cut Group put out a call for people in the trade to send us fancy shape stones that they thought had exceptional beauty. We would take what was there and work a small range of proportions either side to increase the yield and achieve a level of consistancy that is totally missing in the market at present (I think even Mr Grossbard would agree). We would give the info to the stone supplier and a period of grace where they would be the only users of this information or IP (offer still stands).
with many proprietary cuts making a pair is difficult. That is wrong.

 

[Rockdiamond]

HI Garry- your last response was actually directed at Yoram's post- but it does raise some points.

When you put the call out for attractive fancy shapes, what kind of response, and stones did you see?
Is it possible that different shaped colorless rough- specifically more shallow rough- cutters might aim for different goals, as opposed to a brilliant facet design (red heavy aset) type of stone that more closely resembles a fancy colored facet design.
I have seen many lovely Modified Brilliant Cushions, and or Radiant cuts that more closely mock a more typical fancy colored type of sparkle. The type of stones that will be heavy on green and white in the aset.