Uncovering the Truth: The Differences Between Man-Made and Natural Diamonds

[Antiphon]

I place no weight in your informal poll of 4 people. I do place a great deal of weight on investment, sales and diamond news through good sources. You'll have to bring a lot more to the table than four people you walked up and asked to make much of an argument for anything. You have put far too little study into this.

Have a look at Gemesis sales and you'll see you are simply incorrect. The demand is huge and the supply tiny. That will change in the future.

I'm not saying they don't sell. I'm saying that most women don't
want it as an engagement ring for sentimental reasons. Admittedly
my sample is size it small but I don't take surveys for a living.

Upon vising the link you gave, I found this right up top:

“We just sold our 29th stone”

I think this only helps my own case, not yours.

 

[Locrian]

I think this only helps my own case, not yours.

Only if you didn't read the article. One single store selling a 29th stone in six weeks is not shabby at all. Besides, they state later one reason they haven't sold more is that there isn't enough production; when Gemesis makes more, the store will sell more. In the future, please actually read the references I provide.

My suggestion to you is to let it go. This experiment is already in progress. The results, over the next two decades, will tell us who is right and who is wrong.

 

[Locrian]

I, contrary to most people, do not want "real" diamonds. From the characteristics that I've read, real diamonds are rather good electron secondary emitters. This is a nasty property for what I want to use it for.

This statement embodies a property of CVD diamond that deserves more attention in this thread. One of the great things about CVD is the amount of control you have over the diamond you are growing. You can affect the crystallinity, hardness, optical properties, grain size, amorphous content, electrical properties - you name it. Of course, many of them are interrelated, so this sometimes requires research, and there are only so many combinations available - but once you have your choice of growth conditions down, switching between types of diamond is quite easy.

I thought this paper was a good example of what I'm talking about:

Zimmermann et al, "Ultra-nano-crystalline/single crystal diamond heterostructure diode" Diamond & Related Materials 14 (2005) 416– 420

From the abstract:

A new type of highly rectifying diamond heterostructure diode is demonstrated. The p-type doped part of the diode consists of a single crystal diamond, the n-type part of a nitrogen doped ultra-nano-crystalline diamond (UNCD) layer. IV-measurements show 8 orders of magnitude of rectification (F10 V) at room temperature. The barrier behavior is rather complex and can be described by two junctions acting in parallel, reflecting the UNCD properties. This new material system displays an extraordinary thermal stability and has been tested successfully up to 1050 8C in vacuum. Thus, this novel diamond heterostructure diode belongs to the few ultrahigh temperature stable electronic devices.

 

[ZapperZ]

Yes, yes. But where are my penetration depth data? :)

Zz.

 

[Chronos]

I ran across this yesterday. Thought you might it interesting:
http://bold.oma.be/EuroDiamond2000_final.htm

 

[ZapperZ]

Oh, I forgot that I posted here and didn't check it till just now. :)

Thanks for the reference, Chronos. I have seen that paper and unfortunately, they didn't give the exact info that I needed.

However, I decided to follow the "paper trail" by looking at one of their published papers, and upon checking some of the references, I found close to what I'm looking for. A paper by D.R. Kania et al, Diamond and Related Materials v.2, p.1012 (1993) has a figure with the mean free path of photons of various freq. in a CVD diamond. It includes the photon energy that I want. Unfortunately (is that always the case?), they didn't cite where they got this data from, or if they did it (if they did the experiment themselves, their paper severely lack the experimental details). Besides, this paper is more than 10 years old. I'd like to find newer measurements to verify this result.

So my hunt continues...

Zz.

 

[Locrian]

I can't access papers before about '95 over the web, but I'm willing to place a bet that the information in that article is not about UNCD diamond, nor does it apply well to UNCD diamond.

That's the real kicker in your search as far as I'm concerned. These different diamond grain structures affect their electronic propertiesy. UNCD is an interesting diamond type because, unlike NCD diamond, it has a very low amorphous content. I think it will prove dramatically different in its optical properties than microcrystalene and single crystal diamond.

 

[ZapperZ]

I can't access papers before about '95 over the web, but I'm willing to place a bet that the information in that article is not about UNCD diamond, nor does it apply well to UNCD diamond.

That's the real kicker in your search as far as I'm concerned. These different diamond grain structures affect their electronic propertiesy. UNCD is an interesting diamond type because, unlike NCD diamond, it has a very low amorphous content. I think it will prove dramatically different in its optical properties than microcrystalene and single crystal diamond.

And I agree. That's why my hunt continues. I really need to know the penetration depth for UNCD for 5 eV photons. The properties of CVD diamonds are used only as ballpark figures.

Zz.

 

[Astronuc]

I can't access papers before about '95 over the web, but I'm willing to place a bet that the information in that article is not about UNCD diamond, nor does it apply well to UNCD diamond.

Besides "elsivier and diamdns&rel materials", there are the proceedings of the Materials Research Society (www.mrs.org[/url]) and E-journals available from Institute of Physics (IOP - [url]www.iop.org[/URL]). However, I am not sure how easy it is to search for specific information, such as the penetration depth of 240 nm UV in UNCD!.

There seems to be some research in UNCD at UIUC and PSU.

 

[eternalenemy]

Cubic Zirconia and Diamonds=the difference

In fact, it seems difficult to say with certainty which is http://www.fourseadiamonds.com/forum/cubic-zirconia/166-cubic-zirconia-vs-diamonds.html but it all appears easy once you know some facts about both diamonds and Zirconia.