Color improved by cut

[Jcm412]

I have read a few posters make comments about diamonds looking a lot whiter or colorless because of the quality of cut. Often times they are far outside of the near colorless grades. Is there any rule of thumb to tell if this applys or is it all a visual thing?

I am looking on eBay and some other sites and have trouble seeing if some have a yellow tint or not.

 

[TC1987]

Yes, it's true. The make also affects it, i.e. stones with points or square corners like pear, marquise, princess concentrate color in the point or corners.

RB in the modern H&A cut have a good bit of brilliance and more white light (brilliance) can help wash tint.
Ideal symmetry and crown and pavilion angles in a modern RB = good light reflection and less leakage, so that makes tint less evident. (vs. something like, say, a diamond cut just to retain ct weight and not cut for best performance.)

Larger diamonds concentrate tint more than smaller ones.

A diamond with a high crown and small table and a great depth, like a deep Old European Cut or an antique cushion might show more tint (might) because more fire reflected back = less white reflected back.


What lab grades it is a clue, too. AGS and GIA are strictest. EGL USA or other EGL might overrate the color by two grades.

 

[bunnycat]

Yes- a really well cut stone is going to return light better than a poorly cut stone, and so color will probably be less evident.

When a stone is poorly cut, say deep, as it's been said color gets concentrated and so will be more noticeable. (In the case of fancy colors, they tend to cut to intensify that).

You really can't judge color from a photograph. Color is judged in controlled conditions in an unmounted stone. The type of metal a stone is in can also affect it's perceived color. Fluorescence can also affect a stones perceived color.

And if you are trying to judge color on old cuts from photographs, things seem to be all over the place. I think it's something you just have to see in person.

 

[Christina...]

I agree with the others color is really something you need to see in person. While an ideal cut J will look whiter and brighter than a poorly cut J, it's important to understand that a well cut J will still show body color.

 

[Niel]

Yes. Take for example the opposite effect seen in fancy colored stones. You see so many pears, radiants, and ovals in fancy yellow, and rarely see rounds. The fancy pinpoint type shapes trap the light more thus holding more color.

 

[Rockdiamond]

In my experience:
It's not accurate to directly equate how well cut an RBC stone is to how much color it shows.
A few reasons:
there's variations within the colors- and as we go down the scale, the variation within each color is wider.
So a "high D" and a "low D" are very close ( but there is a difference)
But once we get to J, a stone that just missed getting an I color, VG cut grade, may appear whiter than a stone that just missed getting a K, with an EX cut grade.
And there's other factors as well.
In general "super ideal" diamonds tend to have higher crowns and smaller tables.
Sometimes a larger table, shallower crown (yet still within GIA EX) may actually be better at hiding color than a stone which will be considered a better cut, such as a super ideal.
Christina makes a great point- if one is concerned about color, J is not a good idea, even in a super ideal.

About Fancy Colors- it' not that they "trap the light"- but in many cases the goal is to have it bounce around a bit, before it exits. They let it out- but they play with the light a bit more before they give it up

 

[Jcm412]

Ok, so I have been looking at a lot of larger OECs and a lot of them have a color grade of K- N and from the picture most appear very white and a lot of people say they appear colorless. Would these have a very noticeable yellow to them?

 

[Rockdiamond]

HI jcm,
The basic design of an authentic Old Mine Brilliant promotes white light return. Same for most of the newly cut reproductions - in this regard, it's similar to a Round Brilliant.
If we compare an N color Round, or a traditional Old Mine Brilliant to a "crushed ice" style cushion or radiant, the OMB, or RBC will "face up" much whiter.

 

[Lula]

HI jcm,
The basic design of an authentic Old Mine Brilliant promotes white light return. Same for most of the newly cut reproductions - in this regard, it's similar to a Round Brilliant.
If we compare an N color Round, or a traditional Old Mine Brilliant to a "crushed ice" style cushion or radiant, the OMB, or RBC will "face up" much whiter.

I agree with what David (RockDiamond) said in this post and in his previous post. But I'd like to add, from my experience, AGS 0 ideal cut grade diamonds with high crowns and small tables and short lower girdle facets have a lot more contrast brilliance than what my eye prefers. And the dark-light contrast seems to bring out the tint in diamonds I color and lower. In some lights, diamonds in the I-J range will look very white, but in other lights they may appear tinted. Some people find this unappealing; others don't.

 

[Christina...]

HI jcm,
The basic design of an authentic Old Mine Brilliant promotes white light return. Same for most of the newly cut reproductions - in this regard, it's similar to a Round Brilliant.
If we compare an N color Round, or a traditional Old Mine Brilliant to a "crushed ice" style cushion or radiant, the OMB, or RBC will "face up" much whiter.

I agree with what David (RockDiamond) said in this post and in his previous post. But I'd like to add, from my experience, AGS 0 ideal cut grade diamonds with high crowns and small tables and short lower girdle facets have a lot more contrast brilliance than what my eye prefers. And the dark-light contrast seems to bring out the tint in diamonds I color and lower. In some lights, diamonds in the I-J range will look very white, but in other lights they may appear tinted. Some people find this unappealing; others don't.

This is interesting Lula. I have a J 55 36 40.5 and was super surprised by the amount of body color that I could see through the pavilion of the stone. I had an I asscher and while it's not apples to apples, the I was much whiter in the same view angel, so it's interesting that you mention the table and crown angles as being a possible culprit, I hadn't considered that before. I had sort of chalked it up to differences in cut and that my I was possibly a high I and my J was probably a low J, so perhaps it's a bit of both.

 

[Lula]

HI jcm,
The basic design of an authentic Old Mine Brilliant promotes white light return. Same for most of the newly cut reproductions - in this regard, it's similar to a Round Brilliant.
If we compare an N color Round, or a traditional Old Mine Brilliant to a "crushed ice" style cushion or radiant, the OMB, or RBC will "face up" much whiter.

I agree with what David (RockDiamond) said in this post and in his previous post. But I'd like to add, from my experience, AGS 0 ideal cut grade diamonds with high crowns and small tables and short lower girdle facets have a lot more contrast brilliance than what my eye prefers. And the dark-light contrast seems to bring out the tint in diamonds I color and lower. In some lights, diamonds in the I-J range will look very white, but in other lights they may appear tinted. Some people find this unappealing; others don't.

This is interesting Lula. I have a J 55 36 40.5 and was super surprised by the amount of body color that I could see through the pavilion of the stone. I had an I asscher and while it's not apples to apples, the I was much whiter in the same view angel, so it's interesting that you mention the table and crown angles as being a possible culprit, I hadn't considered that before. I had sort of chalked it up to differences in cut and that my I was possibly a high I and my J was probably a low J, so perhaps it's a bit of both.

Hi, Christina -- I think you're probably right that it's a combination of factors. I have seen "high" and "low" I's and J's. And the stone's undertone -- whether it's brown or yellow or grey -- makes a difference, too. But I also agree with David that diamonds with larger tables and lower crowns and shallow depths -- especially combined with longer lower girdle facets (80% or a little larger) have a whiter, brighter look. They have a splintery sparkle rather than a chunky flash. I think the "chunky flash" creates a lot of dark-light contrast. As many people on PS have mentioned, lower colors in old cuts often enhances the antique-look of the cut.

 

[CharmyPoo]

Hi, Christina -- I think you're probably right that it's a combination of factors. I have seen "high" and "low" I's and J's. And the stone's undertone -- whether it's brown or yellow or grey -- makes a difference, too. But I also agree with David that diamonds with larger tables and lower crowns and shallow depths -- especially combined with longer lower girdle facets (80% or a little larger) have a whiter, brighter look. They have a splintery sparkle rather than a chunky flash. I think the "chunky flash" creates a lot of dark-light contrast. As many people on PS have mentioned, lower colors in old cuts often enhances the antique-look of the cut.

I might be off my rocker here but here is my thinking. I have noticed that old cuts face up whiter than MRB and I have heard this mentioned on PS many times. My belief is that old cuts are also characterized by high crown, smaller table and shorter LGF. If this is true, then wouldn't it be contrary to what you and David are saying in that diamonds with larger table, lower crowns, longer LGF appear whiter?

 

[Christina...]

I think charmy makes an interesting point too. i don't have much personal experience with old cuts but i do often hear that they tend to face up much whiter than their color grade suggests. its been my personal experience that larger tables and shallow crown angle combs tend to appear very white as well and had always considered that its because they tend to display much more white light return than a more traditional tolk type cut. My stone favors colored light return as i understand old cuts do so it would seem that it doesn't explain why so many old cut owners feel that theire diamonds appear whiter to them than its color grade its interesting to think about. do larger table shallow crown types appear whiter through the pavilion as well or are we considering face up color only

 

[bunnycat]

Hi, Christina -- I think you're probably right that it's a combination of factors. I have seen "high" and "low" I's and J's. And the stone's undertone -- whether it's brown or yellow or grey -- makes a difference, too. But I also agree with David that diamonds with larger tables and lower crowns and shallow depths -- especially combined with longer lower girdle facets (80% or a little larger) have a whiter, brighter look. They have a splintery sparkle rather than a chunky flash. I think the "chunky flash" creates a lot of dark-light contrast. As many people on PS have mentioned, lower colors in old cuts often enhances the antique-look of the cut.

I might be off my rocker here but here is my thinking. I have noticed that old cuts face up whiter than MRB and I have heard this mentioned on PS many times. My belief is that old cuts are also characterized by high crown, smaller table and shorter LGF. If this is true, then wouldn't it be contrary to what you and David are saying in that diamonds with larger table, lower crowns, longer LGF appear whiter?

I tend to agree with Charmy on this.

I do agree that a stone like a 60/60 stone might tend to face up whiter since it's going to have more white light return than fire. Perhaps transitional type stones (which can sometimes have pretty big tables) might fit in with that. But, people do tend to say regardless that old cuts in general tend to face up whiter than a MRB and I tend to agree.

I'm sticking to my original suggestion that color is hard to perceive in a photo regardless of the make (old versus new) and with old cuts may even be harder to perceive and you just have to see it in person and see if it's a color you can live with regardless of the stated color especially if you are looking at online photos from people who don't have any idea at all how to take even a mediocre photo of small shiny objects.

 

[Rockdiamond]

Hi, Christina -- I think you're probably right that it's a combination of factors. I have seen "high" and "low" I's and J's. And the stone's undertone -- whether it's brown or yellow or grey -- makes a difference, too. But I also agree with David that diamonds with larger tables and lower crowns and shallow depths -- especially combined with longer lower girdle facets (80% or a little larger) have a whiter, brighter look. They have a splintery sparkle rather than a chunky flash. I think the "chunky flash" creates a lot of dark-light contrast. As many people on PS have mentioned, lower colors in old cuts often enhances the antique-look of the cut.

I might be off my rocker here but here is my thinking. I have noticed that old cuts face up whiter than MRB and I have heard this mentioned on PS many times. My belief is that old cuts are also characterized by high crown, smaller table and shorter LGF. If this is true, then wouldn't it be contrary to what you and David are saying in that diamonds with larger table, lower crowns, longer LGF appear whiter?

I tend to agree with Charmy on this.

I do agree that a stone like a 60/60 stone might tend to face up whiter since it's going to have more white light return than fire. Perhaps transitional type stones (which can sometimes have pretty big tables) might fit in with that. But, people do tend to say regardless that old cuts in general tend to face up whiter than a MRB and I tend to agree.

I'm sticking to my original suggestion that color is hard to perceive in a photo regardless of the make (old versus new) and with old cuts may even be harder to perceive and you just have to see it in person and see if it's a color you can live with regardless of the stated color especially if you are looking at online photos from people who don't have any idea at all how to take even a mediocre photo of small shiny objects.

This has been a point I've made for years- and it's been seen at times as controversial.

Older cuts, in general, seem to hide color as well as- if not better in some cases than any MRB.

 

[Karl_K]

When discussing this it is important to clarify that there is gemological color(material color) which the lab grade is based on and apparent color.
Cut does not have a great effect on the gemological color until you get into the fancy range where diamonds are graded face up.
Which is why I have a problem with a vendor saying it faces up whiter, yes it might be true but the pricing is based on the gemological color grade not the apparent color. This was at one time abused.
When viewing it from the side and in some lighting cut don't help and color will be just as apparent.

 

[CharmyPoo]

When discussing this it is important to clarify that there is gemological color(material color) which the lab grade is based on and apparent color.
Cut does not have a great effect on the gemological color until you get into the fancy range where diamonds are graded face up.
Which is why I have a problem with a vendor saying it faces up whiter, yes it might be true but the pricing is based on the gemological color grade not the apparent color. This was at one time abused.
When viewing it from the side and in some lighting cut don't help and color will be just as apparent.

Karl - I am keen to know your opinions on the perceived (not gemological) face up color of a diamond based on cut. More specifically, do you believe that "short lfg, high crown, small table" or "long lgf, short crown, large table" contribute to a perceived whiter face up color? Or does it not make a difference at all.

 

[Rockdiamond]

Great points Karl- although it's still somewhat a grey area- comparing the gemological color ( through the pavilion) used on "white" diamonds, and face up color, as is used on Fancy Colors.
In one sense, we can point to a comparison of two stones with identical body color through the pavilion that show a different face up color as proof that the cut has an impact on perceived color.
Also - we have another grey area which is stones of the lower alphabet (U-V, W-X, and Y-Z)- where the evidence seems to point to the fact that GIA does indeed look at the face up position in these colors.

We know from experimenting with Yoram that the angles on the pavilion of older style cuts have a tremendous affect on perceived color in the face up position.
So, in that sense, cut does indeed impact color.

I share your skepticism of sellers who try to imply that better cut =better color.

 

[Karl_K]

Karl - I am keen to know your opinions on the perceived (not gemological) face up color of a diamond based on cut. More specifically, do you believe that "short lfg, high crown, small table" or "long lgf, short crown, large table" contribute to a perceived whiter face up color? Or does it not make a difference at all.

It is not that easy, what really matters is does the light go in and out taking the shortest path or does it bounce around. The tint of the material can make a difference also in some color ranges.
For a round stone the pavilion and lgf angles make the biggest difference.
For example the pavilion mains start entrapping color around 41.4 degrees and it gets worse very quickly at 41.6 degrees. The crown angle has some but little effect one way or the other.

Every cut design has different angles where they start to entrap color.
This can be a good thing if you are trying to increase the face up color but not so good otherwise.
For example if you want to cut with the goal of producing face up color you find the angle that particular cut starts to fall off the slope with entrapment and with precision cutting cut near that point to get more color while still producing a good looking diamond.
It is tricky because if you don't go far enough you don't get the color but if you go to far the diamond is duller than it should be.

 

[InnaR]

I recently had very interesting experience with color.
I had a stone, graded by EGL USA as K/SI1. The cut bothered me so much, that I decided to recut it.
After a recut it was sent to AGS lab and came back as ...K/SI2.

I am not worried about clarity, it's 100% eye clean. But the color....!!!

Before I sent it for a recut, I predicted that after the recut it will come back from AGS at least few grades lower, but it did not! It does appear much much whiter then it was before.

The only explanation I can come up with, is that in this case the cut did improve the color and while being overgraded by few color grades prior to recut by EGL lab, after the recut the stone received a true K by AGS.

 

[Karl_K]

The only explanation I can come up with, is that in this case the cut did improve the color and while being overgraded by few color grades prior to recut by EGL lab, after the recut the stone received a true K by AGS.

The material was a k the whole time hence the gemological grade of K in both cases.
The old cut entrapped light and increased the apparent color and the new cut down played the apparent color by letting light in and out efficiently.

Cut does not change the gemological(material) color grade enough to really matter, until it gets to the range where they consider face up color as part of the gemological grade.

 

[Laila619]

Karl - I am keen to know your opinions on the perceived (not gemological) face up color of a diamond based on cut. More specifically, do you believe that "short lfg, high crown, small table" or "long lgf, short crown, large table" contribute to a perceived whiter face up color? Or does it not make a difference at all.

It is not that easy, what really matters is does the light go in and out taking the shortest path or does it bounce around. The tint of the material can make a difference also in some color ranges.
For a round stone the pavilion and lgf angles make the biggest difference.
For example the pavilion mains start entrapping color around 41.4 degrees and it gets worse very quickly at 41.6 degrees. The crown angle has some but little effect one way or the other.

Every cut design has different angles where they start to entrap color.
This can be a good thing if you are trying to increase the face up color but not so good otherwise.
For example if you want to cut with the goal of producing face up color you find the angle that particular cut starts to fall off the slope with entrapment and with precision cutting cut near that point to get more color while still producing a good looking diamond.
It is tricky because if you don't go far enough you don't get the color but if you go to far the diamond is duller than it should be.

Yep, that's what I've read too--steeper pavilions can trap body color.

 

[Christina...]

I thought it might be interesting to revisit this thread started by Oldminer a while back. I'm wondering what all of you think? Would you like to see labs implement a sub category for color grading stating the face up appearance of the stones color as well as it's gemological color?

[URL='https://www.pricescope.com/community/threads/face-up-color-versus-body-color-grading.116208/']https://www.pricescope.com/community/threads/face-up-color-versus-body-color-grading.116208/[/URL]


eta: apologies if this is a thread jack but I that it could be considered relevant.