Science of Diamond: like a prism... so colorless means more rainbow?

[MoonRiver]

Dear all,

i read my old science text book and realise that the rainbow colors are due to the dispersion of light by refraction. So if the diamond is well cut, let assume that it is, the next factor will be color?

A colorless well cut diamond will disperse more rainbow than a yellow tinted diamond right?

Since it is simple science that yellow is seen by the eyes because the color is being reflected..
of course clarity is important as any inclusion can obstruct the path of light...

so in general... does it mean that when the diamond is well cut, it best to stick to near colorless and VS diamonds? thanks..

 

[chrono]

No. The dispersion of colour is essentially the breakup of light (regardless of the colour of the body colour of the diamond) into spectral colours aka rainbow. To get more dispersion, the stone must be well cut. Depending on the cutting style, it can lean more towards white light return, a balanced mix or more coloured light return (rainbow or fire). I have many well cut diamonds with colours from E to L and all of them return rainbow colours to the eye very well. However, since my L OMC is cut for coloured light return with the chunky faceting, it shows the best rainbow colours, better than my E coloured EC.

 

[whatmeworry]

In theory, I agree with you that color and clarity can affect dispersion. But in practice, it would have to be extreme examples to have a visible effect.

 

[Stone-cold11]

Agrees with chrono, no. I think you are making the simple mistake of confusing between color light and color object.

 

[Lorelei]

Date: 6/23/2009 12:22:08 AM
Author:MoonRiver
Dear all,

i read my old science text book and realise that the rainbow colors are due to the dispersion of light by refraction. So if the diamond is well cut, let assume that it is, the next factor will be color?

A colorless well cut diamond will disperse more rainbow than a yellow tinted diamond right?

Since it is simple science that yellow is seen by the eyes because the color is being reflected..
of course clarity is important as any inclusion can obstruct the path of light...

so in general... does it mean that when the diamond is well cut, it best to stick to near colorless and VS diamonds? thanks..

I seem to recall reading from one of the experts that the tone of the fire/ coloured light might differ slightly from colourless and warm colour diamonds, I don''t know if either would exhibit more rainbow colours than the other. As to the passage of light being obstructed by inclusions this is possible and might be picked up by sophisticated measuring equipment but might not be something the human eye could ever pinpoint.

 

[MoonRiver]

Date: 6/23/2009 4:03:12 AM
Author: Stone-cold11
Agrees with chrono, no. I think you are making the simple mistake of confusing between color light and color object.

Hi stonecold,

please explain. i am confused. so the colored object is the color that is being reflected in out eyes... the color light dispersed is another thing? so if it is a yellow diamond, will there be also rainbows? i''m quite lost as i am eyeing on a small low color diamond as a fun ring... haven''t committed.

(assuming that the cut is all good and ideal)

 

[Stone-cold11]

Date: 6/23/2009 7:27:03 AM
Author: MoonRiver

Date: 6/23/2009 4:03:12 AM
Author: Stone-cold11
Agrees with chrono, no. I think you are making the simple mistake of confusing between color light and color object.

Hi stonecold,

please explain. i am confused. so the colored object is the color that is being reflected in out eyes... the color light dispersed is another thing? so if it is a yellow diamond, will there be also rainbows? i'm quite lost as i am eyeing on a small low color diamond as a fun ring... haven't committed.

(assuming that the cut is all good and ideal)

Color of an object is due to the object reflecting the light not absorb. Color of light is the full spectrum being split up. For example, primary color of light is red, green, blue, combine to give white, while primary color of paint/pigments is yellow, cyan, magenta, combine to give black. This link will explain better, http://www.diycalculator.com/sp-cvision.shtml#A4

So for the stone, unless it is totally yellow, only transmitting the yellow spectrum, other component color spectrum is still in there and you will still see rainbow colors.

 

[oldminer]

Light emitted in the same body color of the diamond whether as a result of disperion or just the body color transmission, will not appear as part of the fire your eyes can detect. It may go unnoticed, but body color actually does not change the amount oif dispersion, but just may alter the visible amount of it. Well cut diamonds have a good amount of fire, but you can find some relatively poor cuts which could make a lot of fire on occasion, too. Fire and cut quality are not in a perfect relationship. The amount of fire is highly dependent on light sources, etc, while light return is far more cut quality related.

 

[Ellen]

Here's a thread on the same question, asked not too long ago. Thought you might like reading it.

https://www.pricescope.com/community/threads/does-color-affect-fire.104076/

 

[Lorelei]

Date: 6/23/2009 8:50:15 AM
Author: Ellen
Here's a thread on the same question, asked not too long ago. Thought you might like reading it.

https://www.pricescope.com/community/threads/does-color-affect-fire.104076/

Clever Ellen, thats the thread I was thinking of! So according to Garry, the answer to the original question is yes.

 

[Ellen]

Date: 6/23/2009 8:51:44 AM
Author: Lorelei

Date: 6/23/2009 8:50:15 AM
Author: Ellen
Here''s a thread on the same question, asked not too long ago. Thought you might like reading it.

https://www.pricescope.com/community/threads/does-color-affect-fire.104076/

Clever Ellen, thats the thread I was thinking of! So according to Garry, the answer to the original question is yes.

 

[Moh 10]

I've been thinking about this subject a lot since I'm about to receive a purplish-pink (PP) diamond today.
Obviously the diamond itself will look PP, but under spotlight conditions will the flashes of rainbow colors it gives off look more PP?

I suspect the answer is yes but the amount of tinting caused by the light passing through that little bit of body color will be slight.
I'm anxious to see if it is even noticeable to my eye.

Let's imagine a little experiment . . .
Place two diamonds of identical size, clarity and cut, one a D and the other a colored diamond (let's pick yellow). . .
Place them both perfectly level, side by side, under spotlighting . . .
Move your head to get, say, a strong flash of green out of each of them . . .
I suspect if you used a fancy scientific instrument the green flash coming from the yellow diamond would BE more yellow . . .
BUT . . .
I doubt the human eye is sensitive enough to be able to detect the difference.

The opposite of yellow is violet.
So I think if there is a difference in the rainbow flashes given off by colorless vs. a yellow diamond, then violet is where it would be easiest to detect.
In theory violet flashes should be slightly less intense coming from a yellow diamond since the yellow diamond material will absorb violet more than any other color.

I may be wrong about this and I'm really looking forward to studying my little PP diamond when it arrives.
Of course I don't have a D VVS1 white diamond that is identically cut to compare it too but I'm really curious to see if I can tell if the rainbow of colors it gives off looks more purplish pink.

Another test is to placed those two diamonds side by side next to a white wall and carefully compare the entire rainbow spectrum the both project onto the wall.
Maybe I'll try that and post pics.

 

[strmrdr]

colorless

 

[strmrdr]

yellow

 

[strmrdr]

Deep brown orange

 

[strmrdr]

My opinion, lighter colors up to fancy yellow range there wont be a lot of difference.
Brown or brownish or deep yellow takes a fire color hit.

 

[oldminer]

We never can be certain if a consumer means a scientific difference or a visible difference. To some people, an absolute difference, even if not visible to our human eyes is enough to base a decision on. To others, no visual difference is all that counts. We don't want to mislead anyone and at the same time we don't wish to confuse people. Here, we had a thread which began "Science of diamond". Then I would believe this particular person's main interest in in absolute facts opposed to the simplicity of what is only humanly visible.

The diamond business is undergoing a great deal of turmoil as grading diamonds is currently based on humanly visible differences while the edge of science is taking us into grading diamonds in far more minute detail and with far many more gradations of color and light performance than we can visually appreciate. For those among us with scientific outlooks, the facts are what counts. For the artists and the romantics, it is our human perception which must be satisfied. I am trying to balance these two forces: science and romance. It is a strange marraige.

 

[strmrdr]

Date: 6/23/2009 1:12:38 PM
Author: oldminer
We never can be certain if a consumer means a scientific difference or a visible difference. To some people, an absolute difference, even if not visible to our human eyes is enough to base a decision on. To others, no visual difference is all that counts. We don''t want to mislead anyone and at the same time we don''t wish to confuse people. Here, we had a thread which began ''Science of diamond''. Then I would believe this particular person''s main interest in in absolute facts opposed to the simplicity of what is only humanly visible.


The diamond business is undergoing a great deal of turmoil as grading diamonds is currently based on humanly visible differences while the edge of science is taking us into grading diamonds in far more minute detail and with far many more gradations of color and light performance than we can visually appreciate. For those among us with scientific outlooks, the facts are what counts. For the artists and the romantics, it is our human perception which must be satisfied. I am trying to balance these two forces: science and romance. It is a strange marraige.

well said

 

[ericad]

Date: 6/23/2009 1:12:38 PM
Author: oldminer
For those among us with scientific outlooks, the facts are what counts. For the artists and the romantics, it is our human perception which must be satisfied. I am trying to balance these two forces: science and romance. It is a strange marraige.

This is the most well articulated statement I''ve read in a long time - it really resonates with me personally, being an old cut and low color lover, but is such a valuable perspective for anyone searching to define "perfection" in a diamond, which will differ from person to person.

 

[joelly]

This is interesting. Feel like I am in my physics class again.

 

[John P]

Date: 6/23/2009 1:12:38 PM
Author: oldminer
We never can be certain if a consumer means a scientific difference or a visible difference. To some people, an absolute difference, even if not visible to our human eyes is enough to base a decision on. To others, no visual difference is all that counts. We don''t want to mislead anyone and at the same time we don''t wish to confuse people. Here, we had a thread which began ''Science of diamond''. Then I would believe this particular person''s main interest in in absolute facts opposed to the simplicity of what is only humanly visible.

The diamond business is undergoing a great deal of turmoil as grading diamonds is currently based on humanly visible differences while the edge of science is taking us into grading diamonds in far more minute detail and with far many more gradations of color and light performance than we can visually appreciate. For those among us with scientific outlooks, the facts are what counts. For the artists and the romantics, it is our human perception which must be satisfied. I am trying to balance these two forces: science and romance. It is a strange marraige.

Nicely said Dave.