Talk:Synthetic diamond/Archive 1

History
Summary section appears to have been vandalized. I see a Brave New World reference (2540s) and reference to the Lord of The Rings (Middle-Earth). - semi-anonymous 2009-10-20 18:34 —Preceding unsigned comment added by 198.185.66.249 (talk)

The history section seems much too bulky to me. When this happens is it typical to break it off into its own separate article, or just pare it down? PitOfBabel 16:44, 31 July 2007 (UTC)

July 22nd Revision
Overall I felt this article was not well organized, and I made changes to both shorten and clarify it.

I removed the "types of synthetic diamond" section and added a "properties of synthetic diamond" section instead. This isn't a perfect solution, as there are a couple of catch phrases in the old section that may need to be introduced again elsewhere. However, on the thole the "types" section merely listed what other sections already should have stated, and I don't think it was enlightening.

I also shortened the CVD diamond section and moved most of it to its own article. I'd actually like to do the same with HPHT if enough information can be added to warrant it.

The two important things that need to be done I haven't gotten to yet are to organize the applications section (group the applications under headings) and add more information about diamond gemstones and the confusion behind the word "synthetic". Let me know if you think this is heading in the right direction.PitOfBabel 17:42, 22 July 2007 (UTC)

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)

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.

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

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)

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)

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)

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 ~ender 2004-09-04 MST 19:22
 * (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.

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)

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)

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)

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 |&#9786; 23:08, 20 February 2006 (UTC)

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)

It seems that many are using the term CVD synonymously with polycrystalline. I haven't found homoepitaxi mentioned anywhere. See also the Marchywka Effect links, lots of good citations. I guess with nanotubes and actual deployment by Euroepans of a VUV detector, as well as supconductivity, adding to buckeyballs soot and pencils, there is a lot to cover. Not sure how best to organize it but no where on wiki did I see homoepi...

Nerdseeksblonde (talk) 13:02, 26 June 2009 (UTC)

sp3 bonded carbon
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&#9733; 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)

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)

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)

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.

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)

Economics
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)
 * Perhaps the $5/carat figure was for the very cheap raw materials (methane, hydrogen, etc) without taking into account the cost of the machinery or salaries of the technicians. TheWarlock 19:57, 11 May 2007 (UTC)

The consumable materials involved in HPHT are highly refined and purified in order to achieve gem-quality results, and are not inexpensive. The growth units and the labor costs of the scientists are the largest costs involved. Each machine runs for one full cycle lasting many days to weeks, though many times the diamond may have stopped growing part way through, or became so heavily included, the usable gem-quality is minimal. The failure rate is still high which causes the overall costs to go up. Once a rough is available, the costs are very similar to the mined diamond industry. Cutting a rough diamond is usually a few hundred dollars per carat of rough. It is not uncommon to have 50% or more loss of material from rough to polished. Though the costs are not revealed by the manufacturers, the retail prices are readily available from the gem-quality manufacturers websites (example). In general for a one carat, an orange yellow is around $2,500, a yellow is around $4,000, a blue is around $10,000 and a colorless is around $6,000. EEFranklin (talk) 21:32, 4 March 2009 (UTC)

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)

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)

Properties of synthetic diamond section
Someone has misunderstood the title and has began describing how properties of diamonds are observed. Instead, the section should list and detail the properties of a synthetic diamond. Can someone please remove and add information regarding the properties of a synthetic diamond, and possibly comparisons to a ground diamond. --78.86.117.164 23:58, 6 October 2007 (UTC)

Assessment comment
Substituted at 15:54, 1 May 2016 (UTC)

Synthetic diamond is a loaded term
The term synthetic diamond implies that it is somehow artificial and not the same as natural diamond (which is a neutral term). Isn't Man-made a better term, the synthetic diamond page could just link there. — Preceding unsigned comment added by 195.184.122.26 (talk • contribs) 14:11, 21 April 2007 (UTC)


 * I don't consider it a loaded term. Synthetic things are often of better quality than natural things.  People who favor "natural" things usually do so through conditioning, not because of any implications inherent in these terms. Agateller 11:10, 6 May 2007 (UTC)


 * Well, to me synthetic definitely suggests different, whereas "natural" and "synthetic" diamond are primarily the same. I, too, believe it is a loaded term - however, I also believe we're stuck with it.  "Lab grown diamond" is my personal preferred description, as it accurately points out the fact that the biggest difference between the types of diamond is not what they are, but how they came into being. PitOfBabel 15:16, 27 May 2007 (UTC)


 * I believe it's a loaded term, but probably OK to use provided there is a clear explanation that they are (or at least can be) chemically identical. The current revision of the page explains this rather well.  As a chemist, whether something is natural or synthetic is irrelevant if they're chemically the same.  It's something I try to explain to friends but some people believe natural means healthier or just better.


 * De Beers is giving these machines to diamond dealers that can supposedly detect synthetic diamonds. I doubt that they work all that well (if at all), but give the synthetic diamond industry another decade or two and no machine will be able to tell the difference.


 * If you're going to invest, invest in gold - it'll be a long, long time before anyone can make synthetic gold at a profit. ZZYZX 16:50, 10 July 2007 (UTC)


 * You may very well be right chemically, but obviously a diamond is all about emotion. Hence loaded or not loaded, that is what the thing is: a synthetic diamond, and some argue it should be called lab-created, cultured whatever your stance, Wikipedia is not really involved (or really NOT) involved in these political discussions. In the gem world, synthetic stones are a pretty common term, but so are lab-created. Let me check if there is a paragraph on the discussion between "lab-created" and "cultured"... that should cover the contentiousness of terminology Gem-fanat 17:26, 10 July 2007 (UTC)


 * Beware writing this issue off too easily. Currently the phrase "synthetic diamond" means something to most of the public that simply isn't true.  The insistence on using the term is done because natural diamond companies want this misconception to continue (see the way they dealt with the GIA on this issue over the past couple of years as evidence).  It is tacitly accepting the term that is being political, not questioning it.  As a side note, the three billion carats of man made diamond sold each year to industry are not "all about emotion." PitOfBabel 17:36, 12 July 2007 (UTC)


 * Let me give you a link: http://www.farlang.com/diamonds/parsons-synthetic-diamond/page_001 An article of 1893 titled "Synthetic Diamond". If you search their library for synthetic diamond you will find 4-5 more references (articles of books) that have used that term over the decades, including GE's breakthrough in 1955 http://www.farlang.com/diamonds/gregory-oppenheimer-biography/page_016/view?searchterm=synthetic%20diamonds

So I am not so sure it's a recent campaign by the natural diamond companies (i.e. de Beers). it is pretty clear that in scientific circles, "synthetic" means from synthesized material and that is exactly what this type of diamond is. Obviously 90 % or more of the synthetic diamonds are used in industry. I am pretty neutral about it, "lab-created" or "artifical" diamond would be a pretty proper name as well. I am curious as to what you mean with the public impression of "synthetic diamonds" that is not true...

Gem-fanat 22:21, 12 July 2007 (UTC)


 * Yes, both are true; in scientific circles it is called synthetic, and DeBeers and others have pushed to stick the term to lab diamonds sold publicly. As with many other words, the scientific and popular interpretation of the word are different.  The public thinks of synthetic diamond as something different that can be used in place of the "real" thing.  Consider this example, where they say "Traditional wisdom tells us that a synthetic creation is usually not quite as good as the original it strives to emulate. (The difference between clothing made of polyester versus silk comes to mind.)"  In that case synthetic is being used to describe something that is fundamentally different but used for the same purpose.  Also note that, on the other side of the spectrum, companies making imitation diamond often call their imitation "synthetic."  More than a few have edited here doing exactly that, one very recently, and this illustrates why lab companies are trying to relabel their product.  Obviously we shouldn't change terms just to suit them.


 * As I said a ways above, I don't think the term can be avoided. However we need to always be aware of these conflicts of interpretation and recognize when to tune the content accordingly.  My point is that this is very much a serious issue and I am glad we are getting to discuss it more. PitOfBabel 00:56, 13 July 2007 (UTC)


 * I have added the words lab-created and artificial in the first sentence.. so perhaps this should frame the context of synthetic more. Let me check if these two expressions actually redirect to synthetic diamonds in wikipedia.. not sure how to do this if they do not..


 * Why not just use the term cultured, which is what most of the manufacturers of man-made diamonds prefer? They would be the experts on this issue, after all. — Preceding unsigned comment added by Rapierian (talk • contribs) 18:31, 26 October 2011 (UTC)

Gem-fanat 15:57, 13 July 2007 (UTC)

DONE !!! Gem-fanat 16:01, 13 July 2007 (UTC)


 * Man made diamonds are not synthetic, as they are composed of generally all the same elements, bonds and structures to that of a natural diamond. Is a GM crop synthetic? Is fresh water from our taps synthetic when compared to natural fresh water? I disagree to saying man made diamonds are synthetic or to say they are "artificial". Something synthetic is plastic, or new different replicas of something natural that does not share all the characteristics to that of the natural one, which is not the case with man made diamonds. Is the fire from a lighter synthetic than to that of nature? If thats the term for using the word synthetic, that whenever a human hand touches a process, then almost everything we consider natural can be synthetic, even orange juice. I guess some people here are working on behalf of diamond monopolies, to keep their investments safe. It's good banks are wise enough to invest in gold and elements which have a limited supply, whereas diamonds are continuously being formed underground. I feel sorry for women who think they have something valuable on their fingers. Please reconsider the so called "synthetic" tag as it does not apply in this case. Sorry guys.--78.86.117.164 00:07, 7 October 2007 (UTC)

Moved from article:


 * Dear Wiki Editors: Please include a note about how the Diamond Association/DeBeers is pressuring the Federal Trade Commission to call these diamonds “synthetic” instead of “cultured.” Perhaps the title of this article should be "lab-created" or “man-made” diamonds rather then siding with the diamond industry and calling them synthetic. This wiki article is a marketing piece in the sense that the success of these man-made diamonds as gem stones will likely turn on whether they come to be known as "synthetic" or as "cultured." Therefore, it seems clear that the very title of this article is not neutral, but rather the result of sophisticated marketing. Here is a helpful article: “Jem Wars” in the Wall Street Journal (Jan. 13, 2007). Unsurprisingly a free copy can be found on a diamond maker’s website http://www.apollodiamond.com/ under the Corporate/Media links. (I apologize for this intrusion. … I'm not really sure how edits work, but I am sure someone will fix my poorly formatted comment promptly. Hopefully they will change the name of this article as well) — Preceding unsigned comment added by 146.145.190.179 (talk)

As the previous posters have pointed out, the term "synthetic diamond" predates any of the terms such as "cultured" or "lab-grown" which are used by the people who market synthetic diamonds, and it is therefore not part of a De Beers conspiracy. As has also been discussed, the fact that something is "synthetic" doesn't make it worse, as opposed to "artificial diamonds" which are not diamonds at all, and could more correctly be termed ersatz diamonds or diamond substitutes. It is true that in the gem trade, "diamonds are all about emotion". As larger quantities of synthetic diamond become available, people will increasingly be faced with the decision of whether to buy a smaller mined diamond or a larger synthetic diamond, and this will moderate the emotion involved. To make my allegiances clear: I work for a health food and supplement company, and am not in any way funded by De Beers. My wife and I are not emotional about diamonds and precious metals, and we both wear stainless steel wedding bands. --Slashme (talk) 10:52, 7 December 2007 (UTC)

Thanks for responding so quickly. I hope you are alerted to messages here. I think your conclusion that the term synthetic is neutral is mistaken. I will assume that you are correct that "synthetic" predates "lab-grown," but the fact that DeBeer's did not pioneer the term does not preclude their marketing teams from trying to brand these gems as "synthetic." Furthermore, your use of the word conspiracy leads me to believe that you might not understand why I find the term lacking neutrality. Of coarse if there was a secret conspiracy to use the word, it would be biased, but that is not what I am contending. I am simply pointing out what is undisputed -- marketing teams are trying to equate these gems with the word "synthetic." Branding like this is very common and falls quite short of any conspiracy theory, but still makes it a non-neutral term. Words and their connotations are extremely influential. That is precisely why the makers of diamonds want them to be called "cultured." Because this article chooses "synthetic" for its title, it declares one camp the winner.


 * It might be true that sellers of mined diamonds are in favour of labeling man-made diamonds as "synthetic", but it is also true that sellers of man-made diamonds are trying to label them as "lab-grown" or "cultured". While the source of the labels is useful in determining their suitability, it is not the only basis for a decision.  We must simply try to determine which term is most accurate.  Who would seriously suggest that we should call synthetic vitamin E "lab-grown" vitamin E, or that we should call synthetic motor oil "cultured oil"?  These terms are simply marketing terms without scientific meaning.  The word "synthetic" is descriptive and accurate and should remain as the title of this article. --Slashme (talk) 14:37, 10 December 2007 (UTC)

I agree that there are persuasive arguments for identifying them as synthetic, but what I found shocking about this purportedly neutral piece is that it did not even mention this debate. What reason is there for not including a one-line disclosure.


 * Actually, the very first sentence says "Synthetic diamond, also called lab-created, manufactured, "lab-grown" or cultured diamond is a term ... ". What more would you want to see? --Slashme (talk) 14:37, 10 December 2007 (UTC)

My bias is obvious: I think synthetic is misleading, and I also think that the word carries a negative connotation in the eyes of ordinary consumers. That said, I would never contend an article would be comprehensive if it did not at least mention the merits for using the word synthetic. —Preceding unsigned comment added by 146.145.190.179 (talk) 00:24, 8 December 2007 (UTC)


 * I completely disagree that it is misleading, especially as the concept is so clearly explained so early in the article. As for the word "synthetic" carrying a negative connotation, that is a challenge that makers of all types of synthetic products must overcome.  The reason that it has a negative connotation is that so many synthetic products were initially inferior to the corresponding natural product due to impurities and lack of stability.  Some synthetic products are now superior to the corresponding natural products, as is already the case for some (not all) synthetic diamonds.  People who buy rope, fishing line, condoms and raincoats don't mind that they're made of synthetic materials, and would normally accept no natural substitutes.  Maybe someday that will also be the case for diamonds. --Slashme (talk) 14:37, 10 December 2007 (UTC)


 * I would also agree that synthetic is the correct term, whether in this particular market (and some others) that term has become loaded whether for good or bad reasons is irrelevant to it being the correct word to use. Trying to fix people's perceptions by imposing a perpetual euphemism treadmill is a pointless waste of time. --86.129.6.0 (talk) 11:53, 20 October 2009 (UTC)

--

My name's Justin Richards. I'm a journalist who has researched lab-created diamonds. The problem with synthetic is that it describes the combination, or synthesis, of two different elements. That is the definition given by Merriam Webster. Diamond formation, on the other hand, involves pure Carbon only. —Preceding unsigned comment added by 71.16.142.42 (talk) 19:06, 28 March 2008 (UTC)


 * Merriam Webster is hardly an authorative source on the way terms are used in physics (or even chemistry), the definition you quote is a fairly poor definition of chemical synthesis. Would you say speech synthesis is the wrong term because it doesn't involve combining any chemical elements at all? --86.129.6.0 (talk) 12:03, 20 October 2009 (UTC)

I agree Synthetic diamond is a loaded term. I would suggest anthropologic diamond or geologic diamond if we need to differentiate whether they are formed as a result of human action or geologic action. After all, you might build a factory (as opposed to a lab) to make diamonds which are every bit as practically useful as geological diamonds to mount on a metal band on a finger.

The usefulness of a diamond on a band is as a result of the ideas it is imbued with, which has been achieved through clever marketing paid for through prices achieved as a result of scarcity. Forgetting the ideas diamond is imbued with, cubic zirconia is just as functional as a gem stone as diamond. We need to remember that diamonds formed through geologic processes have a range of properties in terms of contaminants. Those contaminants appear to be the method to distinguish anthropologic vs geological. It appears the quality and contaminant components of anthropologic diamonds can be very closely controlled using CVD. It is therefore not reasonable to assume that geologic vs anthropologic diamonds can be reliably distinguished today. As mentioned above, it will be increasingly difficult to continue the illusion of scarcity as manufacturing techniques improve. Techniques will likely continue to improve as there are many industrial uses for crystalline carbon. As scarcity falls, and marketing margins fall, we may need to find some other scarce material to imbue the ideas formerly associated with Diamond. DeBeers - You will have to find something other than Diamond! Nick Hill (talk) 15:27, 2 July 2013 (UTC)

Conversion?
3000 degrees Celsius is NOT 5432K. To convert from Celsius to Kelvin you add 273. Now I don't want to make the edit because I don't know which value is correct but this is a glaring error. 124.185.183.122 22:31, 6 September 2007 (UTC)
 * That is correct. Since later on they managed to heat it to 5000K, which is higher and since 3000°C=5432°F, I am assuming the correct temperature is 3000°C.Calamarain 09:50, 7 September 2007 (UTC)

corrected structure type of diamond from tetragonal to cubic
Since the diamond structure is cubic, with space group Fd3m (see for example the "Manual of Mineralogy" 21st edition by Klein and Hurlbut"), I changed "tetragonal carbon allotrope" to "cubic carbon allotrope".Wikimedes 07:17, 2 December 2007 (UTC)

Preceramic polymer subsection deleted
I found and analyzed the original paper JACS 126 (2004) 3191 but saw no proof of diamond synthesis and therefore deleted the "Preceramic polymer" section. Even if the JACS authors were correct in producing diamond, the result is very poorly described and should be

1) Confirmed by other authors. I should note an inconsistency in that JACS paper. The only evidence of diamond is the Raman spectrum, but it is way too sharp for such a synthesis, and the 1320 peak suddenly shifts to 1276 cm-1 upon changing the laser wavelength, which is much too suspicious.

2) Properly described. This Wikipedia article picked up the creams of that paper (easy low-temperature synthesis) whereas the actual growth took 121 hr at 1120 C in Ar flow + 24 hr at 1300 C in air and had very low "diamond" yield. Anybody who tried knows how difficult it is to convert carbon into diamond :-) NIMSoffice (talk) 00:46, 16 December 2008 (UTC)

To NIMSoffice and Materialscientist:

First, we provided bona-fide references - three of them - to back up the poly(hydridocarbyne) entry in Lonsdaleite. Neither one of you have provided a *single* contrary reference to backup your subjective comments.

Second, the JACS 126 (2004) 3191 paper we referenced was peer-revived in one of the most prestigious journals in America - a very high standard for accuracy indeed.

Third, if either of you had bothered to read the other two references we provided you would have found the corroborating X-ray evidence from other authors (Toppare et al):

page 361, section 3.2, Characterization of Diamond, para 2: "The X-ray powder pattern of the ~mixture shows it to consist of Lonsdaleite" from: Toppare L et al. (May 2008). "Facile Synthesis of Poly(hydridocarbyne): A Precursor to Diamond and Diamond-like Ceramics". Journal of Macromolecular Science, Part A 45 (5): 358–363. doi:10.1080/10601320801946108.

page 2776, para 2: "The data represents Lonsdaleite, a hexagonal form of diamond the fit is even better than the one in aprevious work": Toppare L et al. (June 2009). "Electrochemical polymerizatıon of hexachloroethane to form poly(hydridocarbyne): a pre-ceramic polymer for diamond production". Journal of Materials Science 44 (11): 2774-2779. doi:10.1007/s10853-009-3364-4. —Preceding unsigned comment added by SixFingeredMan (talk • contribs) 23:48, 5 August 2009 (UTC)

Gemstones
"The mined diamond industry is evaluating marketing and distribution countermeasures to these less expensive alternatives."

"The three largest distributors have made public statements about selling their diamonds with full disclosure and have implemented measures to laser-inscribe serial numbers on their gemstones." - The external reference only mentions one company stating their intent to laser inscribe. Should this be rephrased? Furthermore, Gemesis only sells rough diamonds so they cannot laser inscribe the polished diamonds. EEFranklin (talk) 22:04, 4 March 2009 (UTC)

Post-FAC1 review
After the first unsuccessful FA nomination, the Enlgish style of the article was brushed up as reflected here. Materialscientist (talk) 23:15, 3 June 2009 (UTC)

Missing information
The article is good on the technology side but not on the socioeconomics.

The article only indirectly indicates why anyone would bother to make synthetic diamond rather than using natural diamond. I would have assumed it was purely because of price; the section on this Talk page has a bit of information, but the article itself does not. Having read the article, it seems that another advantage of synthesis is that you can fine-tune the properties of the resulting diamond to be atypical or unknown among natural diamonds; this is implicit in the Properties section but never actually stated. I presume this tuning will also affect the price.

Also, the article is very circumspect about the use of synthetics in jewellery/gemstones. It seems POV to focus on the opposition of the natural-diamond companies. What about their competitors? How widespread are they? How much cheaper? How do consumers value "naturalness" against price? (The section above is relevant for this.)  Given that diamonds are conspicuous consumption, is price-based competition even feasible? Are there cases of fraud, passing synthetics off as natural? Are firms making efforts to fool the DiamondView and/or make nature-identical synthetics? jnestorius(talk) 09:51, 20 October 2009 (UTC)
 * Very good questions. There are bits of information flying around, such as that companies selling natural diamonds are doing their best to block usage of synthetics as gems, etc. I just never got my hands on enough encyclopedically reliable sources for this topic. Materialscientist (talk) 10:08, 20 October 2009 (UTC)


 * Jnestorius - a late reply, but the reason the socioeconomics aren't mentioned much is that, as Materialscientist suggests, it's very difficult to document that information. As someone who worked in CVD diamond growth in the past, I'd like to answer your questions from my point of view, and you can decide for yourself how reliable the information is.


 * Being able to control the properties of the diamond you make is just about the only good reason to produce synthetic diamond. With CVD diamond growth you can control the conductivity (even making semiconductive diamond), the crystallinity, the hardness, the color, and other properties.  You can also grow diamond directly on a substrate, which gives you options you don't have with mined (or HPHT) diamond.  If you want to use diamond in a variety of circumstances (cutting tools, x-ray diffraction, colored gemstones, heat spreaders), being able to control the properties of your diamond is critical.


 * However, this control has its limitations, and often comes at a price. I would argue the single biggest problem facing CVD diamond growth (and I realize I'm not addressing HPHT much) is the same problem they had in '85 - growth rate.  5 micrometers an hour is just slow.  Now, you can find lots of articles where people have obtained substantially higher rates than that - I know I did.  However, you give up control when you do that, and often the diamond you produce is very specific and/or very low quality.  The other huge issue is substrate size, though in my opinion more progress has been made on that.


 * As far as gemstones go, a lot of people who thought synthetic diamond was going to be a great competitor to mined diamond were in for a shock a decade ago. The reality is that mined diamond isn't that expensive, and by the times it's cut, marketed, stored and sold it's price goes up tremendously.  When you do the same to CVD diamond you end up wiping out most (but maybe not all) of your margin.  There's a reason Apollo Diamond did all its own maketing and sales for so long (though I think they've branched out).  The one area of exception is in colored stones, because they're so rare naturally.  Thus most HPHT (I'm especially thinking Gemesis) have spent most of their time in that area, and we're back to the control argument.


 * I really think the best explanation for why synthetic diamonds haven't had more impact on the gemstone marketplace is because the actual business of selling gem diamond is a lot less dependant on their original source than people think. Of course, technological and business model improvements may well change this situation.  Don't place any money on when.


 * To address one other question you've had, dishonest companies that pass off non-diamond as "synthetic diamond" were very common, even two years ago. This certainly contributed to confusion in the marketplace, but I really doubt it's a big factor.  Try to figure out how much reactor space you need to compete with the amount of gemstone quality diamond mined each year and you'll discover very quickly what kind of effort is needed to really impact the market with synthetic gems.


 * Long ago I had some Diamond & Related materials articles that went into some of this (if you go back far enough you'll see I spent a lot of time on this article, many years ago). I've long lost them.  Maybe I can dig them up, but I doubt it.  More likely this will get deleted and that will be that.  It was fun walking down memory lane though. --PitOfBabel (talk) 18:09, 8 February 2010 (UTC)
 * I never believed CVD would be any good for gem diamonds, and that its only niche is electronic or mechanical coatings. What I saw in the original comment is a hint to those Chinese plants with hundreds of BARS-like presses which can easily produce cheap and reasonably good diamonds. Yellow color and inclusions can be avoided by optimizing the growth; size is limited, but optimized HPHT can result in clear, blue and even orange or greenish stones. Technology has long been developed for that (by Russians and Kanda), but then comes marketing .. Materialscientist (talk) 01:25, 9 February 2010 (UTC)


 * Synthetic diamond has myriad industrial applications, and it is far easier to synthesize it for industrial applications than to mine it (which I suppose might be an economical reason, though it's also a simple utilitarian one)--and I don't know whether polycristalline (PCD) diamond can be mined, and PCD is harder than monocrystal diamond, and lasts longer in industrial use. Sources about this could be found, and used to build up such an explanation in this article. Actually I think the article is potentially missing quite a lot of information on that. --RichardAlexanderHall (talk) 23:40, 16 December 2012 (UTC)

Ashes to diamonds
The ashes from a cremation are sometimes used to make a diamond to be used as a gemstone for sentimental reasons. Should there be a section on this? —Preceding unsigned comment added by 62.12.14.27 (talk) 09:59, 20 October 2009 (UTC)
 * There is a note on that in 1st paragraph of "Gemstones". Materialscientist (talk) 10:08, 20 October 2009 (UTC)
 * This sounds like a bit of a scam. The high temperatures and conditions of cremation should leave only the non-carbonaceous inorganic components of the body in the ashes.96.54.53.165 (talk) 17:08, 20 October 2009 (UTC)
 * Please advice us on ashes. As I understand, and adult produces >2 kg of those, most of which are not carbon, but. Only grams are needed for a diamond. The companies say they oxidize the ashes at high temperature, leaving only graphite, which is then converted. Materialscientist (talk) 09:43, 21 October 2009 (UTC)

High-power switches at power stations
The article refers to one potential use of synthetic diamond being "high-power switches at power stations". Being an electrical transmission engineer, I expect what this means to say is "high-voltage switchgear on transmission systems", but I would need to read the full paper to be sure. It's referenced to: J. Isberg, M. Gabrysch, A. Tajani, and D.J. Twitchen (2006). "High-field Electrical Transport in Single Crystal CVD Diamond Diodes", Advances in Science and Technology 48:73, but that link leads only to the abstract and first paragraph. Does anyone have access to the full paper they could share with me? Thanks, &mdash; BillC talk 17:20, 20 October 2009 (UTC)

Grammar
This phrase is a little preposterous "Numerous claims of diamond synthesis were documented between 1879 and 1928; each of those attempts were carefully analyzed and none were confirmed." Every claim was carefully examine? I am sure there were a number of claims that were just brushed off. Which is fine as science is not required to carefully examine and refute every bogus claim. But saying all were examined without references is a little far fetched. Doc James (talk · contribs · email) 19:31, 20 October 2009 (UTC)
 * Rephrased. Materialscientist (talk) 09:43, 21 October 2009 (UTC)

History line

 * The De Beers Diamond Research Laboratory has grown stones of up to 25 carats (5.0 g) for research purposes. 

Is there a reason this sentence is in the middle of a history section? Did it occur at some auspicious time? Could a knowledgeable editor relocate this statement or else give it the needed context? Comet Tuttle (talk) 22:54, 20 October 2009 (UTC)
 * It is a unique historical growth of largest HPHT synthetic diamonds, which happened some time in the past. If anyone knows more, please let us know. Materialscientist (talk) 09:43, 21 October 2009 (UTC)

"Cultured" diamonds
I noticed the discussion above, which talks about the article name, and whether it should be called "synthetic" or "cultured". It seems to me that the term "cultured diamonds" exists in the industry as being different from squishing a bunch of carbon together, but instead refers to "growing" from a seed.

So, if synthetic covers all non-natural diamonds, and "cultured" diamonds describes a process and a product that is a subset of synthetic, then shouldn't we have a section (namely the Synthetic diamond section), named "cultured diamonds" or "culturing diamonds"? Am I a making any sense? What do you think? Anna Frodesiak (talk) 13:49, 6 February 2011 (UTC)

(By the way, I did notice Chemical vapor deposition of diamond. But that just confused me.) Anna Frodesiak (talk) 13:51, 6 February 2011 (UTC)

Pricing
It would be interesting to have a graph of the price of diamonds (of a certain size or quality or whatever) produced by different technologies over time. In particular, I'm wondering what the impact of synthetic diamonds on the natural diamond market is. -- Beland (talk) 01:18, 3 June 2012 (UTC)

Hardness, and harder forms of diamond which have not been synthesized
The section on hardness lacked any mention of polycrystalline diamond, or PCD (which is synthetic Carbonado), so I added it with links to other articles at Wikipedia which support this. However, it needs direct citation from scientific sources (I don't know but that this article, http://en.wikipedia.org/wiki/Material_properties_of_diamond#cite_note-11 cited in the article Material properties of diamond, may illuminate that. I have run across information on the hardness of all known forms of diamond in GPa, but don't recall where now--and I think it would be useful to compare the different forms of diamond listed in this section, in those terms (GPa). Also, it may be worth noting that several times, Tracy Hall accidentally synthesized ballast (opaque white PCD, which accomplishment was announced in this paper, I believe -- http://www.sciencemag.org/content/169/3948/868.abstract -- and reproduced here also http://www.htracyhall.org/papers/19700427.pdf -- and there seems to be no mention of ballast diamond anywhere on Wikipedia), and that this has not yet been reproduced, and that no one has yet synthesized Lonsdaleite (which is about five times harder than monocrystal diamond) either. Both of these, with theoretical GPa, could be added somewhere here--perhaps under a section entitled "Forms of Diamond Which Have Not Been Synthesized" -- perhaps that could be a sub-section of "Hardness". --RichardAlexanderHall (talk) 16:28, 16 December 2012 (UTC)

Impurities and inclusions vs. Synthetic Diamonds
Under the section "Impurities and inclusions", it says "Every diamond contains atoms other than carbon in concentrations detectable by analytical techniques." However, under the section "Thermal conductivity", it talks about "isotopically pure diamond" that is " Single crystals of synthetic diamond enriched in 12C (99.9%)" according to this article, but "100% 12C or 100% 13C" according to the isotopically pure diamond article. It is my understanding that these diamonds do not have "atoms other than carbon" and invalidates the "Every diamond" statement. Alancnet (talk) 05:09, 18 August 2014 (UTC)
 * Meaningful concentrations are on the order 0.1% (1000 parts per million, ppm) for thermal conductivity, where we talk about carbon-12 and 13, and roughly 1 ppm for "impurities .. detectable by analytical techniques". Note that 13C is an "impurity" for thermal conductivity, but not for most other properties. Materialscientist (talk) 07:34, 18 August 2014 (UTC)