How are treated black diamonds made black? Why do they test as moissonite?

I am looking for something with a citation here if it exists.

  1. I know that black diamonds are treated similarly to HPHT, I have been told by some that there is a coloring agent introduced, and have been told by others that there is not. I can’t find any articles on the subject with more than an opinion.

  2. Treated black diamonds test as moissonite on moissonite testers (but test as treated black diamonds from labs like IGI or GIA). Treated black diamonds also weigh more than ‘white’ diamonds do with the same measurements. (IE: They have a higher specific gravity)


I have read that the stones they use are so heavily included that they test as moissonite because the crystal structure doesn’t read like normal diamonds, I have also been told that this is the reason they have a higher specific gravity.

Again, I haven’t found anything other than opinion on the subject.


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I also would like the answers to that question

Someone must know!

Hello, from what I understand it’s basically gray bort (Industrial Diamond) that has been irradiated which turns it black. Then finally it is cut and polished.

Thanks, do you know if any colorant is introduced during the process?

Pressure? Vacuum?

IGS does have a search engine interesting

Thanks Cold, however, there is not even an entire sentence on the process in the article you linked to.

“…most black diamonds on the market today are either superheated or irradiated to an almost black color

I have yet to see an article explaining the process, if anyone has seen one, I would like to know more.

Those doing the process might be guarding the process. Albeit, it isn’t cheap and very few laboratories know the step by step process. Google man. If the info is there you will find it.


Unfortunately google hasn’t yielded anything as of yet, which is why I was asking on here.

I DID get the answer to the heat conductivity test in another thread, so, half way there!

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