The Diamond Makers by Robert Hazen, Cambridge University Press, 拢9.95,
ISBN 0521654742
HOW ABOUT this for a corny movie plot from 1950s America: a kid named Chucky
sends a chunk of coal to a team of boffins, asking if they will turn it into a
diamond for him. A few weeks later, Chucky gets an envelope鈥攁nd inside is
a single, tiny diamond. Cheesy, huh? Except it happens to be true. It鈥檚 just one
of the many highlights of Robert Hazen鈥檚 compelling book The Diamond
Makers, which tells the story of the boffins who discovered how humble
carbon can be converted into the most glittering celebrity of the gem world.
There are some wild tales here. Take this one. During the 1950s, a man in
Schenectady, New York, used to tell people he could turn peanut butter into
diamonds. The thing is, he could. One day in December 1955, Robert Wentorf went
out to his local food store, bought a jar of crunchy peanut butter, and spread
some in the centre of a huge machine. After leaving it for a while, he opened it
up鈥攖o reveal tiny, green-tinged diamonds.
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The secret behind Wentorf鈥檚 trick was not prestidigitation, but
pressure鈥攖ens of thousands of atmospheres of it, plus searing heat. But
for years, Wentorf told no one how it was done. For he was part of a circle of
scientists at General Electric in the US who knew the secret of making diamonds
from pretty much any form of carbon, from graphite and polythene to roofing tar
and peanut butter鈥攁nd coal of course.
The story of how the GE team succeeded in recreating the conditions in
nature鈥檚 own diamond factory forms the backbone of the book, but botched
attempts to make diamonds date back at least to the 1820s at least, when various
scientists tried to grow crystals from solutions. By the late 1870s, geologists
had realised that diamonds must have been born under enormous pressure, and the
Scottish chemist James Hannay had a shot at replicating the process.
After countless failures, Hannay finally discovered tiny diamonds inside one
of his high-pressure vessels in 1880. Exhausted, he moved away from diamonds to
study other less elusive things. Recent analysis of Hannay鈥檚 synthetic diamonds
has proved them to be natural. Some think his colleagues sneaked some diamonds
into the equipment to put the old chap out of his misery. If the dismal
experiences of those that followed are any guide, Hannay鈥檚 colleagues did him a
big favour.
Bitter dispute
According to the textbooks, the first to succeed were GE鈥檚 Project
Superpressure team in December 1955, using an anvil press applying 50 000
atmospheres and 1250 掳C. But, as Hazen makes clear, a team at the Swedish
company ASEA beat them by over two years鈥攜et said nothing.
Having succeeded in a task that had defeated so many, the GE team was itself
soon split by a dispute over priority. It centred on how the first diamonds had
actually been made. Most of the group insisted they had been formed in the
team鈥檚 so-called cone anvil machine on 8 December. But team member Tracy Hall
had also succeeded in making diamonds the following day, using his own ingenious
machine. Unlike his colleagues, he could repeat his success again and again.
Hall came to resent the credit won by the other team. Thanks to Hazen, an earth
scientist, we now know that Hall was right to feel this way. An internal inquiry
by GE, prompted by Hazen himself, has revealed that what was thought to be the
world鈥檚 first synthetic diamond is not quite what it seems.
I won鈥檛 say exactly what the inquiry revealed; you鈥檒l just have to find out
by reading the book. But on the way you鈥檒l encounter plenty of other weird and
wonderful facts鈥攍ike the crucial role played by Sioux Indian pipes in
high-pressure research.
It鈥檚 not a flawless read. Hazen is surprisingly hard to follow on the physics
behind diamond-making, and his writing style varies from rather florid in the
opening chapters to a bit dull towards the end. Even so, I can鈥檛 help feeling
that had it been more imaginatively packaged like Dava Sobel鈥檚 Longitude
this little gem would be a bestseller. Read it and spread the word.