[meteorite-list] Model Rockets and Moon Rocks was...13.5 kg lunar

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Tue May 17 10:51:27 2005
Message-ID: <9f1k81teeepba8o6v2qqnvoa7uttcubsfc_at_4ax.com>

On Sun, 15 May 2005 17:24:12 EDT, MexicoDoug_at_aol.com wrote:

>I need to add my support to Mark F and Darren's openminded interpretation of
>your negative assessment of the (lack of) feasibility getting Lunar material
>FOB Earth at a cost (mind you, not price) below $5000 per gram. The
>optimistic figure starts at about $1 per POUND, cheaper than any US domestic mail
>product.

Not directly related to this subject, but I was reminded of this debate on wherther lunar material
will always be expensive by this new development on why diamonds won't always be expensive.
I'm sure that the Debeers monoply will continue to try to convince people that a synthetic hunk of
crystalline carbon isn't as good as their natural hunks of crystalline carbon, but I think that
they'll lose the fight. I anticipate the day not many years from now when diamond is almost cheap
per carot as cubic zirconia.

(BTW, the line "The diamond age is upon us" refers to a novel titled _The_Diamond_Age_ by Neal
Stephenson)

http://www.scienceblog.com/cms/node/7908

Real big diamonds made real fast

Researchers at the Carnegie Institution's Geophysical Laboratory have learned to produce 10-carat,
half-inch thick single-crystal diamonds at rapid growth rates (100 micrometers per hour) using a
chemical vapor deposition (CVD) process. This 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.

"High-quality crystals over 3 carats are very difficult to produce using the conventional approach,"
commented Dr. 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, and will be reported at the Applied Diamond Congress in Argonne, Illinois, May 18.

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
situation 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 [1]. Using new techniques, the
Carnegie scientists have now produced transparent diamond using a CVD method without HPHT annealing.

Figure 3. 12 mm (1/2 inch) 5 carat diamond laser cut from a 10 carat single crystal produced by
high-growth rate CVD. The diamond was laser cut (and inscribed) from a diamond block and only
partially polished.

To further increase the size of the crystals, the Carnegie researchers grew gem-quality diamonds
sequentially on the 6 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 (~300 carat) is
achievable.

Finally, new shapes have been fabricated with the blocks of the CVD single crystals. Figure 3 shows
a 12-millimeter anvil that can be used for new types of scientific experiments.

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," concluded Hemley.

From Carnegie Institution
Received on Tue 17 May 2005 11:04:35 AM PDT