Talk:Crystallographic defects in diamond

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This article had been listed and then delisted as GA article. Reason quoted was citations - ie inline citations are lacking. The articles ref's should be reviewed and appropriate citations made to allow easy verification of facts.SauliH 20:13, 4 February 2007 (UTC)
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Crystallographic defects in diamond was a good article, but it has been removed from the list. There are suggestions below for improving the article to meet the good article criteria. Once these are addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.

Delisted version: October 23, 2006


A few notes regarding my expansion:

  • I've tried to explain the theory as clearly and succinctly as I'm able, so I invite anyone with a stronger background in solid state physics to amend or expand as necessary.
  • I did not write a subsection on interstitial atoms; I may get around to this sooner rather than later, but I'm not exactly comfortable in doing so because I can't seem to find references that don't conflict with each other.
  • To Stepanovas: I've included inline references to back up statements where appropriate, so I think it would be helpful if you could do the same for your material (e.g., the C form to A form conversion).
  • I used old-style parenthetical inline refs because I don't really like the Template:Ref style nor its Note equivalent; I reference the same work more than once, which isn't something these templates can do very well.

Any comments or questions? -- Hadal 21:35, 12 July 2005 (UTC)

Hadal, yet again great work! Regarding intrinsic defects, see dislocation for a better grounding in the materials science end (for one, edge and screw are the preferred terms to glide and shuffle). I will try to dig up my solid state physics and physical chemistry texts for some more insight and references. - Bantman 19:41, July 13, 2005 (UTC)
Thanks! I did wonder if the glide/shuffle terminology was idiosyncratic to the authors cited, but I felt it best not to contradict them in the event that the terms had a special meaning in semiconductor research. (A quick Google reveals at least a handful of related publications using the present terms.) I also forgot to link to the dislocation article; it may be best to restructure this article to reflect the former. -- Hadal 04:57, 17 July 2005 (UTC)
old-style inline refs are good. But references, which you added, are not primary. Those are latest works which dose not reflects initial researches and discoveries. I will work at it. Stepanovas 07:36, 14 July 2005 (UTC)
I see you found a primary reference for Kaiser and Bond; thanks for that. The other refs are good enough though, aren't they? Secondary references are fine for Wikipedia, as we're not exactly trying to write a journal paper. Furthermore, the refs I used are considered authoritative in my field; gemmology does encompass some aspects of diamond's crystallographic defects, and to that end I've contributed what I could. Anderson and Payne are as primary as you can get when referencing gem spectra in general. -- Hadal 04:57, 17 July 2005 (UTC)

[edit] Discussion

  • B2 not nitrogenous defect, N3 content never high.
  • aforementioned Cape series What is it?

Stepanovas 15:36, 16 July 2005 (UTC)

  • B2 was already treated as a nitrogenous defect before I arrived, so I wasn't about to contradict that placement without further research. N3 content is not precisely "high", but neither are most the others; we're talking fractions of a percentage by mass in most cases (at least in gem-grade stones). Your "up to one percent by mass" is superlative rather than typical, is it not? In my field, the N3 line is diagnostic for diamond.
  • The Cape series is explained under B1 center, as well as under Material properties of diamond#Composition and color. It's a common term for Type IaA + IaB mixed material, and includes nearly all (98%) diamonds. Since so many diamonds exhibit the N3 line, I thought it pertinent to mention. Do you not agree? I realise the article's emphasis is on IR spectra, but that's just one of several angles of investigation. The N3 line is (IMO) major by virtue of its presence in the visible spectrum and its orchestral relationship with the other defects. It is not major in terms of mass, but it is very persistent. (So why did you remove UV/VIS from the list of methods?)
  • Also, why did you remove my qualifying statement, "... provided the diamond is cooled to very low (ca. -180°C) temperatures"? It is my understanding that cryogenic temperatures are required (or at least a de facto standard) for accurate IR spectra, as diamond is such an efficient thermal conductor: the warmer the diamond is, the more diffuse the spectrum is (due to atomic vibrations). This isn't a new concept, but if you think it's somehow unremarkable, I'll leave it be.
Hadal 04:57, 17 July 2005 (UTC)

because spectops may be recived under different tempersatures.

  • vacansy in diamond is not F-Center because diamond is not ionic crystal.
  • Green color is due defficult defects consisting from nitrogen, vacansies and intersticials.

Stepanovas 15:59, 18 July 2005 (UTC)

  • Irradiated diamonds do have F-Centers: in this context, F-Center is a synonym of color center. See page 4 of this PDF from the Mineralogical-Geochemical Institute of the University of Freiburg or page 2 of this article by Paul F. Hlava of Sandia National Laboratories for two examples of this usage. However, because some authors reserve "F-Center" exclusively for ionic crystals, I've replaced the term with "color center" to avoid confusion. In future, I would appreciate it if you could constructively edit the specific term you have a problem with, rather than simply remove a large chunk of referenced text.
  • The green (and in some cases blue) colour of irradiated diamond is the result of these color centers; the mechanism is fundamentally different than impurity-derived colour. While the vacancies do interact with interstitials, it seems irradiation alone does not produce the high temperatures needed for vacancy migration. Rather, the consensus is that nitrogen-radiation defect complexes are only likely after annealing, which also agrees with my cited references. For further examples, see [1] and [2]. Natural annealing via long-term geothermal heating probably does produce vacancy-nitrogen defects, but the point is that the heat is a required element for NV defect complexes.
  • We have so many references now that I'll likely stick with them when doing future expansions. There's still a bit more info to harvest, such as hydrogen in Type IIc (ooh!) diamonds.
I think the article's maturing nicely. -- Hadal 04:41, 19 July 2005 (UTC)

[edit] Fluorescence and other questions

Agthorr June 15, 2006:

This is a great article. I've learned a lot, but I still have some unanswered questions. I'm hoping some of the authors of the article might be able to find answers for them (or point me in the right direction) and update the article with the additional information.

I've been trying to better understand the blue fluorescence seen in many available-to-the-consumer diamonds. I know its caused by the absorbtion of UV light, exciting an electron, which shortly thereafter radiates blue light. The description of the N3 and N2 centers state that they absorb UV light; are these the centers that cause fluorescence? Or is it caused by a different kind of defect?

I've heard many conflicting reports about the "oily" or "milky" look of fluorescing colorless diamonds. Everyone seems to agree that very strongly fluorescencing stones have the oily look and that mildly fluorescing diamonds are fine. For moderate and strong fluorescence I find a lot of disagreement. Some people swear up and down that all such stones appear oily. Some people swear up and down that all such stones appear oily when viewed under significant UV lightly (e.g., daylight). Some people (such as this GIA report) state that *only* very strongly fluorescencing diamonds exhibit the oily or milky appearance. Finally, other people state that the oily or milky look depends on the particular stone, and some strongly fluorescing stones have it, while others do not.

Based on what's in the article now, I get the sense that a milky look could be the result of many colorless defects (such as A or B1 centers) that don't alter the color of the stone, but nevertheless reduce transparency. Is that possible? Do A or B1 centers lead to translucency (as opposed to transparency)?

[edit] Delisted GA

This article has been removed from the Ga list as it has failed WP:WIAGA criteria 2b. Feel free to renominate the article once these issues have been addressed. Tarret 23:42, 23 October 2006 (UTC)