Pink Diamonds

[Rank Amateur]

I heard a guy on the radio today talking about colored stones. Most of what he referred to (and sells) were treated stones.

He said that blue was caused by Boron but we can''t figure out what causes pink. I found it hard to believe that the "what causes pink in diamond" nut hasn''t been cracked.

 

[valeria101]

There does seem to be some ambiguity about this color, but I wander how much. All reports I came across mention some distortion of the crystal lattice as origin of the shade, but also note that this is not a definitive result. But, since pink and red diamonds have been created and colored artificially, it should be well known by now what the recipe is. Do you know?

 

[Rank Amateur]

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On 10/30/2003 10:51:23 PM valeria101 wrote:

Do you know?----------------

I've no idea.

I just found it hard to believe we don't know what causes pink.

As an aside there are more and more ads on the radio for different dealers touting their expertise in colored diamonds. I wonder if WebZ has experienced a big uptick in biz.

R/A

 

[mike04456]

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On 10/31/2003 11:49:08 AM Rank Amateur wrote:





I just found it hard to believe we don't know what causes pink.


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Actually, there are a number of gems, not just diamonds, for which the cause of color is not understood. You're talking about some pretty advanced solid state physics, especially when you get into colors that are not caused by trace elements like boron. You have to do a lot of spectroscopic analysis to determine precisely what colors exist in a gem, and then try to correlate the spectra to what you know about the crystal structure and chemical composition. Pink in diamonds is generally believed to be caused by what's called "plastic deformation" of the crystal structure, but it has not been conclusively established. These atomic lattice defects are known as "color centers" because they can selectively absorb certain wavelengths of light, in this case, the green region around 550 nm. However, no one has yet identified such a color center in pink diamonds or determined what its structure might be.

 

[Richard Sherwood]

I've read that the body color in Argyle pinks is commonly associated with pink graining in the stone.

Australian Wayne at MDX would probably know more on the subject. He sells pinks, if I remember correctly.

 

[mdx]

Our Current view is the pinking effect is a result of lattice damage due to tension;

Dr. Hollis will soon be doing some trace element analysis on some chips of Argyle pinks.
We will post the results if any once the tests are complete.

Wayne
Melbourne Diamond Exchange Ltd ( Australia)

 

[mdx]

Our Current view is the pinking effect is a result of lattice damage due to tension;

Dr. Hollis will soon be doing some trace element analysis on some chips of Argyle pinks.
We will post the results if any once the tests are complete.

Wayne
Melbourne Diamond Exchange Ltd ( Australia)

 

[Gemxpert]

Colored diamonds.. yes a fascinating subject.

Yellow type Ia stones containing nitrogen aggregates such as the N-3 center which absorbs in the visible region at 415nm known as the cape spectrum. 99% of all diamonds will show a 415nm due to the N-3 center.
Type Ib diamonds are much more rare in fact most Ib yellows are synthetic.

Most pink diamonds are of type Ia (containing nitrogen) in various forms. However, the color is explained by "plastic deformation" or a structure that is deformed at the "slip planes".
Some pinks are of type IIa (nitrogen free) so in this case the color would only be from the plastic deformation not nitrogen. This is why there is still some research to do.

To produce a pink diamond by irradiation and heat.. you need to start with a diamond that has single nitrogen (Ib). After irradiation and heat.. you will end up with a stone that is mauve, pink etc.

Not only type IIb's are blue. Most are though and they are electrically conductive - not insulators like more diamonds. Some blues are natural irradiation blues, some with hydrogen etc.

Detection involves using a VU-VIS/NIR spectrometer and liquid nitrogen as a coolant -196c temperature.
Looking for lines such as the 595nm line is proof of treatment. The subject goes on and on.
Thanks for letting me ramble on. I enjoy this line of work.

 

[elmo]

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On 11/7/2003 8:34:32 AM Gemxpert wrote:

Thanks for letting me ramble on. I enjoy this line of work.

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Please keep on rambling

. It is one of the best ways that us interested consumers keep on top of these things.