Talk:Synthetic diamond

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Diamond Synthetic diamond is part of WikiProject Gemology and Jewelry, which aims to improve Wikipedia's coverage of Gemstones, Jewelry, and related topics. If you would like to participate, visit the project page.
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A peer review for this article would be beneficial. It may be GA, and could advance to FA with some additional work. Inline citations appear at a cursory glance to be partly in place.SauliH 06:50, 5 February 2007 (UTC)
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Contents

[edit] Diamond simulants

Isn't any page about artificial diamonds incomplete without mentioning cubic zirconia's as diamond substitutes?

Cubic Zirconia is not diamond, so this would probably best fit under "Related article" or "See also".
Acegikmo1 18:08, 23 Jul 2004 (UTC)

[edit] History

What about James Ballantyne (Hannay), I think (although it would require some verification) that he claimed to have produced very small synthetic diamonds in the 1880s by heating carbon under pressure in a kiln, a claim which was widely disputed at the time. However his 'diamonds' were sent to the british museum of natural history where upon rediscovery some years later they where found not only to be real diamonds, but also of a type consistent with synthetic construction.

[edit] Yellow tint

The following sentence is contradictory:

"The yellow tint occurs when less than five out of each 100,000 carbon atoms in the diamond crystal lattice are replaced with nitrogen atoms. Technically it is a contaminant, but colored diamonds are more profitable because they can be made more quickly, cost less to manufacture, and are very popular".

The part that says "Technically it is a contaminant, but [...]" implies that there is too much contaminant. Which is wrong ! Because the synthetic process naturally leads to these low levels of contaminant (nitrogen atoms).

Or maybe the error is that "[...] when less than five out of [...]" should be replaced by "[...] when more than five out of [...]". In this case the sentence would be perfectly logical. -- R. Duxx


I think it means that ANY number of non-carbon material is in the lattice that technically it is a contaminant, though in this case a desirable one. Dalf | Talk 09:29, 11 May 2005 (UTC)


You don't get my point (or maybe I don't understand you :P). No, it is not desirable to have contaminant (because if we had too much contaminant, there would be no yellow tint). -- R. Duxx
I think I can clarify what was meant. When some of the carbon atoms are replaced by nitrogen atoms, a yellow tint results. This tinting will occur even if the proportion of carbon atoms replaced is less than five out of every 100,000. The replacement technically constitutes a contaminant, but it makes the diamonds more profitable nonetheless.
Does this make sense? -Acegikmo1 00:42, 4 December 2005 (UTC)
I think Duxx's point is that 0 is less than 5, and if 0 atoms are replaced, then you don't have a yellow tint. It's a valid comment, so replacing "fewer" (which had replaced "less") with "approximately" would make sense. I'm replacing it with "as few as approximately". Elvey 16:43, 20 December 2005 (UTC)
Thank you Elvey, I wasn't able to clearly explain my point, but you understood me anyway :-) And you fixed the article, yeah ! This thread can now be deleted from the talk page since the issue has been resolved. I'll leave it to someone else (wikipedia admin ?). -- R. Duxx

[edit] CVD Process

Another statement is contradictory:

"[it] uses the low-pressure technique of chemical vapor deposition (CVD) to produce [diamonds]. The diamond produced is a single crystal, as opposed to the polycrystalline patchworks formerly produced by CVD."

So basically it says "it uses CVD to produce diamonds which are not like the ones produced by CVD". What a pity, after having read this article about diamonds, I am now even more confused...

The newer technology of low-pressure CVD produces a single crystal, but the older methods of CVD (at ambient pressure) produced polycrystalline patchworks. Acegikmo1 00:44, 4 December 2005 (UTC)

[edit] CVD and UV

Can anyone explain why "Synthetic diamonds retain ultraviolet light just as well as any type of light while natural diamonds usually retain light outside the visible spectrum poorly"? If LP CVD produces chemically & physically correct diamonds, why should they exhibit different spectral properties? Frankie 04:13, 1 January 2006 (UTC)

I'm not sure what is meant by them "retaining" light at all. It actually sounds to me like they are saying the optical properties of CVD diamond are better than natural diamonds, which would make sense. Both natural and CVD diamonds have contaminants (even if they are transparent), it is just a matter of how much and what type. PitOfBabel 20:15, 30 January 2006 (UTC)

[edit] High Temperature, High Pressure (HTHP)

(A process) developed by Gemesis, makes diamonds that may contain impurities in about 100 hours, by mimicing the natural process.

Statements where reasonable people may disagree

  • HTHP, developed by Gemesis
    • HTHP stands for High Temperature High Pressure. This adjective is used in other contexts (such as color treatments), besides lab-grown diamonds.
    • Many lab-grown gems (such as sapphires) are subjected to HTHP color treatments in addition to the process(es) used to grow the gem.


A minor nit, but its HPHT rather than HTHP when used as an acronym in the industry.

Also, Gemesis did not develop HPHT, they refined the reproduceability of the process using the smaller BARS system. The russians (at Novosibirsk) invented the washing machine size BARS press, which Gemesis imported and refined. --CarbonElemental 06:57, 23 December 2005 (UTC)

[edit] Chemical Vapor Deposition (CVD)

CVD, chemical vapor deposition, builds diamonds by precipitation from carbon plasma and builds up at half a millimeter a day, and has a theoretical limit of several inches.

Statements where reasonable people may disagree

  • (CVD diamonds) are said to be flawless in clarity.
    • Many industrial CVD diamonds are quite cheap. (About $1 per carat, for diamonds that are a few centimeters long and a fraction of a millimeter thick.) Unfortunately, many of these diamonds are golden-brown, like a well-done cake.

~ender 2004-09-04 MST 19:22

One has to be careful with the price statement because it is not really clear what industrial CVD diamond really is. If it is a polycrystalline material, then indeed it can be rather cheap because it grows on various substrates (Si, glass, etc.) and the growth parameters are not really that demanding. On the contrary, the monocrystalline material is grown only on diamond (usually Ib HPHT) and Ir substrates and is very slow, as was pointed out, what makes the price rather high. Colour of the final layer depends on the process, now it is possible to grow layers which are rather pure and suitable for electronic application. If someone is interested I would advice to have a look at Elsevier's journal "Diamond and related materials". ~And 2005-10-5

There is an apparent contradiction between the claim that CVD single crystal diamonds cannot be grown to more than a few millimeters in radius and the claim that the Carnegie Institute's process can be extended to grow a 300 carrot stone. Logicnazi 07:54, 12 February 2007 (UTC)

Should be fixed, thanks for pointing it out. PitOfBabel 18:28, 13 February 2007 (UTC)
The CVD diamond can be grown larger, it is merely that the seed wafer that is used limits the size. With each progressive growth stage a new wafer is cut, and the seed is slightly larger than the previous. An article appeared in wired.com about this see this link SauliH 22:23, 13 February 2007 (UTC)

[edit] History

I'm somehow skeptical that only two minor companies should be listed as making synthetic industrial diamonds. I was under the impression that the technique existed quite before these companies (not for making diamonds suitables for jewelry, but for making diamonds for industrial uses, i.e. tools). David.Monniaux 05:02, 11 May 2005 (UTC)

The two listed companies are attempting to sell synthetic diamonds as gems. There is a large industry (about 400 million carats produced annually, or 4 times natural production) supplying synthetic industrial diamonds. I will try to update the article with this information in the next few days. - Bryan is Bantman 06:04, May 11, 2005 (UTC)

[edit] Molten nickel

I was under the impression that nickel is used as a catalyst/solvent in the production of industrial diamonds. If someone can find a source for this, it should really be in the article.--Joel 8 July 2005 01:51 (UTC)

[edit] Be careful which companies you link to from this article

The information posted below by “samboy” on 26 September 2005 is false and misleading. No where on the our website does Diamond Nexus Labs, Inc. “admit they are selling CZ”. To our knowledge “samboy” has not done any scientific analysis of the chemical composition and physical properties of our gemstones. The Diamond Nexus gemstone is a complex polycrystalline substance, and detailed information on our gemstone science is available on our site. Deeper information, including the complete chemical rubric for the stone is available by contacting customerservice@diamondnexuslabs.com.

Wikipedia has been notified that “samboys” posting is erroneous, oversimplified and uses trademarked information without our permission.

When discussing the quality, composition, or any other property of your product, we will use your products name and your website's information freely and without your permission. I'm dissapointed any company would try to restrict a persons right to discuss a topic by claiming IP rights, though I'm not surprised. PitOfBabel 14:02, 24 February 2006 (UTC)

There are a number of places out there that sell Cubic zirconia marketed as a "synthetic diamond". These are not diamonds; the gems in question are not made out of compressed Carbon. Diamond Nexus labs admits they're selling CZ here (ZrO2 is the chemical formula for Cubic zirconia); Russian Stone Company admits it here: "If a natural diamond jeweler uses a natural diamond tester on a synthetic Russian stone, they will most likely, in error, state that our product is a standard cubic zirconia. This is not true, our synthetic Russian Stones will not change color or clarity and are so durable that it will scratch glass.". On This page it states "Russian Diamonds: Including Russian Brilliants, Russian Stars and others, they are in fact nothing but high quality cubic zirconias. This is not mentioned prominently on their web sites and they will only cop to it when pressed, but that is the fact." (Of course, the same is true for the "Diamonds" that Diamond Nexus Labs sells). Samboy 09:56, 26 September 2005 (UTC)

  • Neither website claims to sell sythetic diamonds (at least, not now). ··gracefool |☺ 23:08, 20 February 2006 (UTC)

[edit] Current issues facing CVD diamond

An anonymous poster removed the section on CVD diamond problems, writing: "removing the "problems." CVD research has largely been exhausted. Other methods do not depend on surface area, so problem 2 is meaningless. And CVD is no longer slow."

Working in the field I can state emphatically that CVD research is hardly exhausted; on the contrary, it is experiencing a revival across the world. While research funding has shown boom-bust cycles in the US, other parts of the world have been making steady progress, especially Asia. There are many areas that have not been adequately researched, such as the most effective method of diamond n-type doping, the most acceptable method of radiation detection, methods of depositing uniform diamond, doped uniformly over large substrate areas, etc.

Surface area is a very serious issue for CVD diamond growth. What the anon revisionist means by "other methods do not depend on surface area" would be interesting to find out. There are some recent breakthroughs in microwave plasma CVD that have improved sufrace area, but the uniformity is questionable and reproducibility low. I think Fraunhoffer has made progress in that area, but they haven't had much of an impact on the market. I am certain there is no US company producing large diamond wafers in any significant quantity; otherwise the navy wouldn't be beating down doors looking for a supplier for radar windows. As for non-microwave based plasmas, arcjet still only coats small areas. Only hot filament shows much promise for area, but this comes at a high cost; the chemistry at tungsten filaments is even more complex (in undesirable ways) than in other plasma systems. I know of companies that coat larger areas with hot filament reactors, but their growth rates are incredibly low.

Saying CVD is no longer slow suggests a lack of understanding about how diverse the area is. There have recently been some really incredible growth rates demonstrated at a few universities, but these are the exception rather than the rule. They operate in very specific parameters (very high pressure/power) that cannot be used in other circumstances. Deposition rates such as these cannot be done on most substrates (such as silicon) for many reasons, especially thermal stability of the substrate and adhesion. So it is true that some CVD isn't slow, but is absolutely not true that CVD isn't slow.

The anon person did make a great point though by adding another problem to the list; economics is a very serious issue for CVD diamond. However, note that this is primarily because of the problems they erased. Methane, hydrogen and electricity are cheap. The problem preventing economic success in most areas is quality of the diamond, surface area coated and rate of coating.

Comments welcome.

PitOfBabel 21:35, 15 December 2005 (UTC)

[edit] sp3 bonded carbon

four sp³ orbitals
four sp³ orbitals

The Chemical vapor deposition, CVD section mentions sp3 bonded carbon, I could find no information anywhere on wikipedia about an sp3 bond, only an sp2 bond. What is an sp3 bond and should an article be created for it? -- Atlanta800 21:56, 15 February 2006 (UTC)

An SP³ bond is just another type of Orbital hybridisation. --ThrashedParanoid★ 03:54, 16 February 2006 (UTC)
To add a little more information, when it comes to carbon, the structural difference between pencil lead and diamond gems is that pencil lead, which is graphite, is sp2 bonded carbon, while diamond is sp3 bonded carbon. Part of the trick in creating synthetic diamond is not creating graphite instead. PitOfBabel 13:45, 24 February 2006 (UTC)

[edit] Apollo Diamond

Someone added the following to the page: "White diamonds, however, are still lacking in clarity, and at projected costs, do not offer any greater value for the price (http://diamondcuttersintl.com/diamond_education/articles/reference/apollo.html), (http://www.gia.edu/newsroom/issue/2798/1842/insider_newsletter_details.cfm#3)"

Both of those articles are several years old, neither makes any real argument about the price, and the "lacking in clarity" business is a poor assertion not validated by either article. There is no doubt Apollo is having issues; they were supposed to be selling gems back in 2004, and still don't have any significant number on the shelves. I would be interesting hearing real reasons why this could be, but neither of those articles really gives answers. Removing until someone provides better evidence for these opinionated assertions.

PitOfBabel 14:12, 14 March 2006 (UTC)

From the GIA article: "Clarity was equivalent to VS1 to SI2; some small and irregularly shaped gray-black inclusions were observed in some samples, due to deposition of diamond-like carbon or graphite (as suggested by Raman spectroscopy)." Compared to other synthetic gem diamonds (Gemesis), the maximum clarity (VS1) is significantly lacking by comparison to "internally flawless" (http://www.gemesis.com/specs_3.htm). Also note that the only white diamond produced by Apollo that I could find reference to on the web (see GIA article) is tiny at 14 points. By all accounts, Apollo diamonds tend to be brown (not white). Perhaps I should have noted the color issue to start. Yes, both of these articles are several years old, but they are the most recent, and the GIA article is one of, if not the only, technical description of Apollo diamonds. Some parts of this section read like a press release from the marketing department. I suggest other references to the price of Apollo diamonds (even relative statements like "cheaper than natural") be removed, since no evidence is cited to support those claims.

I agree about removing the information about their pricing; I think in the synthetic diamond section we could just remove any and all speculation concerning Apollo Diamond entirely. I have seen other technical descriptions in patent literature, but I don't believe that information any more than I believe anything else that's been printed about their gems. That pricing seems weird to me anyways. Its been a few years since I shopped for diamond rings, but $4000 doesn't sound like %30 less than market price for a VS1 diamond. I suppose that's a different discusion though. PitOfBabel 16:44, 15 March 2006 (UTC)

Damian: Apollo Jewelry was "coming soon" back in November of 2003. If it's alright, let's just say their gemstones are not available, and we'll update when they actually are. PitOfBabel 16:16, 11 April 2006 (UTC)

[edit] Separating CVD diamond growth

I am considering creating a new article for CVD diamond growth and leaving a short introduction here. I've been busy, but I suspect I will take care of this in June.

Any comments, or objections? PitOfBabel 13:50, 27 May 2006 (UTC)

Yes, what?, no PVD? -lysdexia 23:33, 25 September 2006 (UTC)
Who produces diamond with PVD? People use PVD primarily for DLC coatings, not sp3 bonded diamond. It certainly doesn't deserve its own article. I stil haven't decided if CVD really deserves it's own page, and am not sure when I could find time to gather enough information to warrant it. I'll have to think about it.PitOfBabel 11:25, 30 September 2006 (UTC)

[edit] Category

This just got moved from the category Diamond to the category Synthetic Diamond. This doesn't make sense to me. It seems to me that this should still be left in the category Diamond as well. Making the change; if you disagree post here please.

[edit] The Dead's ashes diamond

I don't know if this is true, but I heard, unrelaibly, that some funeral homes are taking the carbon of dead people and turning it to diamond for their famillies...sort of a fancy advance on the urn of ashes...

Initially it was pets someone was... diamondifying... but Lifegem does humans now.PitOfBabel 04:50, 30 November 2006 (UTC)

[edit] Economics

Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion.
This article has been tagged since January 2007.

What is the cost per stone of making synthetic gem-quality diamonds by these various processes? -- Beland 16:54, 20 December 2006 (UTC)

I do not know what the cost per stone for HPHT methods is. Figuring a cost per stone for CVD diamond growth is essentially impossible for anyone but the company themselves. The ingredients are dirt cheap - methane is easily available and a few tanks will last for years. Hydrogen is even cheaper. The electricity involved is not expensive. However, the cost of a good CVD reactor can be anywhere from $200k to several million. Apollo diamond probably paid on the low end of that scale, but only they know for sure. Then there is the cost of the technicians - because this is a fresh technology, they are paying people with PhD's in materials science and physics to work with these machines, which makes payroll significant. In conclusion, it is very difficult to pare down and figure the final cost of a gem for these companies without a great deal of information they'd rather us not have. The estimate I sometimes hear, thanks to a terrifically bad article put out by Wired, is $5/carat, and you can be assured that is completely absurd. It could not be less than a few hundred dollars per carat, and may be more. To complicate matters worse, the price/carat will change significantly as each company progresses. As unhelpful as this was, I still hope it helps. PitOfBabel 06:03, 23 December 2006 (UTC)

[edit] Gem Color

In the "Synthetic Gems" section, the article states that "Colored diamonds are more profitable because they can be made more quickly, cost less to manufacture, and are very popular." My understanding is that colored diamonds are substantially less valuable on the market than clear diamonds. Clear diamond is 100 times more expensive than black diamond, and it is also substantially more valuable than the yellow diamond that is often found in mines. Gemologists often discuss the clarity of diamonds, as this is a deteriming factor in their value. Thus if synthetic diamonds are colored, and not clear, then they are LESS profitable compared to clear ones (not MORE profitable). It is also stated that "...greater measure of control allows Apollo Diamond to produce diamonds of various colors, from pink to black." I think that the assertion about colored diamonds being more profitable is an error and should be corrected. Colored diamonds are less valuable than clear ones and black diamond is worthless for gems (black diamond is used only for industrial purposes). I also think that there should be some mention of whether or not there currently exists a known process for the synthesis of CLEAR diamonds. --Anonymous 11:36, 24 December 2006 (UTC)

You're incorrect about diamond prices. A quick look on Blue Nile and Icestore will demonstrate that clear, well cut round white diamonds range from $3300-$3700 depending on quality. Similar quality yellow diamonds average $4500 and reach $8000 for a particularly well colored stone. Natural blue diamonds can start at $50,000. Pink diamonds range from $15,000 and far up from that. Beyond that, in HPHT production it is much, much easier to produce these colored diamonds. Therefore they can produce diamonds that sell for higher prices (though certainly nowhere near a natural one) easier and in greater quantities. They are therefore MORE profitable, not LESS. As for whether there exists a method of producing clear diamonds, CVD companies such as apollo can certainly do this. Gemesis may have very very recently come up with a good way to do this using HPHT, but these have not hit the market yet (and may not have the quality to do so). Hope this helps. PitOfBabel 14:56, 24 December 2006

(UTC)

My wife and I are one of the "invitation only" apollo diamond owners. The salesman at apollo said he had some colored diamonds but he considered them "novelties" and "goof ups from when they were getting the equipment set up right". Also regarding the claim that Apollo diamonds are larger, I don't think that's the case. The apollo diamonds he offered ranged from 0.25 to 0.66 carat or so (all clear with excellent clarity ratings). Maybe they have had trouble getting the larger ones going or something. Gigs 23:57, 6 January 2007 (UTC)
Any information you'd feel comfortable sharing would be much appreciated Gigs. There's been so much hype over Apollo for so long, it's great actually hearing first hand accounts finally emerge.PitOfBabel 06:05, 8 January 2007 (UTC)
What else do you want to know? They offered about 5 or 6 diamonds to choose from based on what I told them we wanted, in various grades, F through VS-1, D-J color or so, and they quickly cycled through these, assumedly as they were purchased and replaced by new stock. Apollo sales guy was very open, he said we could discuss it in public as much as we wanted and repost pictures of the diamonds he sent us if we wanted to. Prices were about the same or very slightly less than retail diamonds in settings really, it wasn't significantly cheaper. It looks good, but I'm no diamond expert. We haven't taken it to be indepedantly appraised or graded, but it's not yellow at all that I can tell, and no occlusions visible to the naked eye. Gigs 02:45, 14 January 2007 (UTC)

[edit] Natural vs Synthetic Quality

Someone requested a citation for the following - "As such, it shares the same material properties and is potentially of an even higher quality than its natural counterpart." The problem isn't that this needs a citation so much as it is possibly subjective. Obviously natural diamond has impurities due to the conditions it is created in. There is no argument that CVD diamond growth can produce diamond with far fewer impurities. That might be worth citing, except that the level of impurities is not necessarily a key indicator of quality. That's the whole point of doping - you can sometimes get better results with specific amounts of key "impurities".

I'll think about how it might be rewritten. In the meantime though it doesn't need citations so much as it needs clarification.

An example of where synthetic diamond is superior to natural diamond is in hardness. Consider Rev. Sci. Instrum. 76, 026112 (2005), Super-hard diamond indenter prepared from high-purity synthetic diamond crystal. Also consider this link: http://www.carnegieinstitution.org/raining_gems.html. That was a simple google search because I knew what to look for, I haven't tried Elsevier yet.

Maybe instead of "higher quality than" we could have "superior in some aspects to". Sounds poorly worded, but might lead to a fair solution.PitOfBabel 21:25, 26 February 2007 (UTC)

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