Posted on 05/16/2005 3:19:04 PM PDT by STARWISE
Crystal-clear material is better for optics, scientific applications
May 16, 2005
Researchers at the Carnegie Institution of Washington, D.C. have produced 10-carat, half-inch thick single-crystal diamonds at rapid growth rates (100 micrometers per hour) using a chemical vapor deposition (CVD) process. The size is approximately five times that of commercially available diamonds produced by the standard high-pressure/high-temperature (HPHT) method and other CVD techniques.
In addition, the team has made colorless single-crystal diamonds, transparent from the ultraviolet to infrared wavelengths with their CVD process.
Most HPHT synthetic diamond is yellow and most CVD diamond is brown, limiting their optical applications. Colorless diamonds are costly to produce and so far those reported are small. This limits general applications of these diamonds as gems, in optics, and in scientific research.
Last year, the Carnegie researchers found that HPHT annealing enhances not only the optical properties of some CVD diamond, but also the hardness. Using new techniques, the Carnegie scientists have now produced transparent diamond using a CVD method without HPHT annealing.
"High-quality crystals more than three carats are very difficult to produce using the conventional approach," said scientist Russell Hemley, who leads the diamond effort at Carnegie. "Several groups have begun to grow diamond single crystals by CVD, but large, colorless, and flawless ones remain a challenge. Our fabrication of 10-carat, half-inch, CVD diamonds is a major breakthrough."
The results were reported at the 10th International Conference on New Diamond Science and Technology, Tsukuba, Japan, on May 12, 2005, and will be reported at the Applied Diamond Congress in Argonne, Ill., May 18, 2005.
"The rapid synthesis of large, single-crystal diamond is a remarkable scientific achievement, and has implications for a wide range of scientific and commercial applications," said David Lambert, program director in the National Science Foundation (NSF)'s earth sciences division, which funded the research.
To further increase the size of the crystals, the Carnegie researchers grew gem-quality diamonds sequentially on the six faces of a substrate diamond plate with the CVD process. By this method, three-dimensional growth of colorless single-crystal diamond in the inch-range is achievable.
Finally, new shapes have been fabricated with the blocks of the CVD single crystals.
The standard growth rate is 100 micrometers per hour for the Carnegie process, but growth rates in excess of 300 micrometers per hour have been reached, and 1 millimeter per hour may be possible. With the colorless diamond produced at ever higher growth rate and low cost, large blocks of diamond should be available for a variety of applications.
"The diamond age is upon us," said Hemley.
If nobody can tell natural from synthetic, there goes the market.
For the moment, synthetics will fluoresce when exposed to hard UV light - eliminate that, and there goes the market. Aside from that, DeBeers is starting to etch its stones with a logo, which has not proven effective, historically speaking - fake Rolexes and knockoff Gucci purses abound, and I expect that fake DeBeers diamonds will too. ;)
I think this is a bit different .. these are real, but created in a lab -- they are not fake.
Diamonds are an element too...it's called carbon.
Huh? $100 a carat times 10 carats equals $1000. For a 10 carat anything to cost over a billion dollars, the per carat price would have to be over one hundred million dollars per carat.
Armed with inexpensive, mass-produced gems, two startups are launching an assault on the De Beers cartel. Next up: the computing industry.
By Joshua Davis
Aron Weingarten brings the yellow diamond up to the stainless steel jeweler's loupe he holds against his eye. We are in Antwerp, Belgium, in Weingarten's marbled and gilded living room on the edge of the city's gem district, the center of the diamond universe. Nearly 80 percent of the world's rough and polished diamonds move through the hands of Belgian gem traders like Weingarten, a dealer who wears the thick beard and black suit of the Hasidim.
Yellow diamonds manufactured by Gemesis, the first company to market gem-quality synthetic stones. The largest grow to 3 carats.
"This is very rare stone," he says, almost to himself, in thickly accented English. "Yellow diamonds of this color are very hard to find. It is probably worth 10, maybe 15 thousand dollars."
"I have two more exactly like it in my pocket," I tell him.
He puts the diamond down and looks at me seriously for the first time. I place the other two stones on the table. They are all the same color and size. To find three nearly identical yellow diamonds is like flipping a coin 10,000 times and never seeing tails.
"These are cubic zirconium?" Weingarten says without much hope.
"No, they're real," I tell him. "But they were made by a machine in Florida for less than a hundred dollars."
A microwave plasma tool at the Naval Research Lab, used to create diamonds for high-temperature semiconductor experiments.
Weingarten shifts uncomfortably in his chair and stares at the glittering gems on his dining room table. "Unless they can be detected," he says, "these stones will bankrupt the industry."
Put pure carbon under enough heat and pressure - say, 2,200 degrees Fahrenheit and 50,000 atmospheres - and it will crystallize into the hardest material known. Those were the conditions that first forged diamonds deep in Earth's mantle 3.3 billion years ago. Replicating that environment in a lab isn't easy, but that hasn't kept dreamers from trying. Since the mid-19th century, dozens of these modern alchemists have been injured in accidents and explosions while attempting to manufacture diamonds.
Rest at link
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Excerpt:
“If you took the same quality of diamond as I have here, and if that were a natural diamond, that would be terrifically expensive,” says Clarke. “A natural diamond of that size and that color and that cut and that quality would be somewhere in the neighborhood of $16,000 to $20,000. We will be selling that somewhere in the neighborhood of $3,500 to $4,000.
Until recently, Clarke knew nothing about diamonds. A retired brigadier general and entrepreneur, Clarke was looking for business opportunities in Russia, when scientists showed him blueprints for something they had developed for the Soviet space program.
It was a diamond-making machine. Clarke bought one, and now, eight years later, he has 23 of them."
Excerpt:
DeBeers
"It is important to dispel a popular misconception. Some diamond retailers suggest that they buy their diamonds directly from diamond mines and that this results in significant cost savings to you, the consumer. In the first place, most of the retailers who make this claim are not diamond cutters. They do not have the capacity to manufacture finished diamonds from rough stones produced in the mines.
Also, for the most part, the distribution of rough diamonds is strictly controlled. An international monopoly known as the DeBeers Corporation buys and distributes approximately 60% of the world's uncut, rough diamonds and controls the prices of the remaining diamond rough indirectly. DeBeers Corporation's "single-channel" marketing of diamonds determines the price of rough diamonds and makes it almost impossible for diamond manufacturers or others to "beat the system" by purchasing rough diamonds at prices significantly below DeBeers' established prices.
How does DeBeers operate? DeBeers Corporation is an international cartel that has controlled the price of diamonds since the mid 1930s. Anglo-American Corporation owns 45% of DeBeers; 40% is owned by the Oppenheimer family, which established DeBeers monopolistic, single-channel approach to rough diamond distribution; and 15% is owned by the government of Botswana.
DeBeers buys most of the world's rough diamonds from diamond producing nations: e.g., South Africa, Botswana, Namibia, Zaire, et al. In addition to purchasing diamonds from major diamond producing nations, in order to maintain control of rough diamond prices, DeBeers purchases a large percentage of the remaining rough diamonds throughout the world from sources outside of the recognized DeBeers network of diamond producing nations.
DeBeers sells these rough diamonds to approximately 80 "sightholders" (generally, major diamond cutting firms) which are the only companies authorized to buy rough diamonds directly from DeBeers. The sightholders are invited to attend a "sight" held at DeBeers Central Selling Organization in London, England approximately ten times a year (acceptance of the invitation is mandatory). Each sightholder is given a box of diamonds.
The price of the diamonds is fixed by DeBeers and is not subject to negotiation. Even rough diamonds marketed outside of DeBeers are priced in accordance with the price structure established by DeBeers' Central Selling Organization.
From 2002 through the beginning of 2005, DeBeers has reduced the number of sightholders from approximately 120 to 80, as a part of it's "Supplier of Choice" program. Under this program, DeBeers will try to consolidate the diamond market from rough production through retail, eliminating many of the current participants in diamond production and sales.
The impact on the diamond cutting industry and jewelry retailers (among others involved in the diamond trade) could be enormous. Does this mean that the price of diamonds will come down? Not on your life! It means that DeBeers and it's sightholders will probably make a greater percentage of the total take from the diamond market than it currently does. "
Rest at link
What's the graphite analogy ? .. not understanding you. Diamonds come from carbon, no?
Quite a difference in the per carat price .. and if they are incredibly beautiful, look real, are flawless .... wouldn't bother me .. less to worry about getting mugged for (it's fake .. it's really fake, I'm tellin' ya.)
Absolutely! They might as well be called the "Diamond Mafia!"
Good grief! I must have been hanging out at DU too much. For some reason, I appended million to that figure. Sorry about that and I really appreciate you pointing that out.
I must have been hanging out at DU too much.
Whew...that's a relief. I was skeert that you maybe worked for DOD or Robert Byrd. : )
Thanks for the information and link. I'm headed there now.
The "lowest energy state" (ie the form which the carbon atoms would prefer to arrange themselves, under room temperature and pressure) of carbon is graphite (layers of carbon atoms arranged in hexagonal sheets).
There is a significant "energy barrier", however, that separates the graphite phase of carbon from the diamond phase - to get to their preferred state, some energy must be externally provided to overcome this barrier.
Here is an analogy: you pay $400/month rent at the west end of town, but there is a place in the south end for $300/month that is just as nice and otherwise equivalent in every way to where you are now. So that *would* be your preferred "state". But there is a cost to moving there that you have to pay, so some additional effort has to be imparted to get there (ie there is a small "hill" in your costs - a one time expense, but after that, you are in a "lower energy state"). Never tried that one before, so I don't know how confusing it is (or if it was even needed!).
But anyway, once the energy barrier is overcome, it is much more difficult for the carbon to re-arrange into diamond (extreme temperatures and pressures, or very involved chemical processes). So, with enough time, one would expect all diamond to at some point be exposed to enough energy to overcome the barrier and turn into graphite. And once it is graphite it stays that way.
So: diamonds are not forever - they eventually will turn into graphite, which *is* forever.
:)
Can they be used in lasers?
Diamonds are the most worthless gemstones in the galaxy.
Even stars form them. They are all over the place.
Still, if they can make a 10-carat diamond in the shape of a block, then it is only a short time now that the next computer chip CPUs will be made from the stuff.
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