Diamonds are forever... diverse

April 2, 2007

A post-doctoral fellow at McGill University has discovered that diamonds may well be forever, but their origins are not necessarily as clear-cut as commonly believed.

Emilie Thomassot, a member of McGill’s Department of Earth and Planetary Sciences, studied nearly 60 diamonds extracted from one fist-sized sample of Earth’s mantle found in a South African diamond mine.

Her findings are highlighted as an Editor’s Choice in the March issue of Science magazine.

This unique sample originated at a depth of about 160 km and breached the surface during an explosive volcanic eruption more than one billion years ago. Thomassot measured nitrogen content and carbon and nitrogen isotopes in the diamonds, which ranged up to nearly 0.2 carats in size.

“This is the first time that anyone has observed such large chemical variation in diamonds extracted from a single sample,” said Thomassot. “The observation was completely unexpected and really turns conventional interpretations of how diamonds form on their head.”

The counterintuitive implication of the study is that gem diamonds may form from methane-bearing fluids circulating locally within the deep Earth, rather than through geodynamically induced mixing of different global carbon reservoirs. Although the existence of a methane-rich diamond-forming fluid has been predicted theoretically, direct evidence had been lacking up until now.

On the Web: Science Magazine March 2007

Source: McGill University

Related Stories

Recommended for you

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...

Exploring the physics of a chocolate fountain

November 24, 2015

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, answering the age-old question of why the falling 'curtain' of chocolate surprisingly pulls inwards rather than going straight ...

Biomedical imaging at one-thousandth the cost

November 23, 2015

MIT researchers have developed a biomedical imaging system that could ultimately replace a $100,000 piece of a lab equipment with components that cost just hundreds of dollars.

'Material universe' yields surprising new particle

November 25, 2015

An international team of researchers has predicted the existence of a new type of particle called the type-II Weyl fermion in metallic materials. When subjected to a magnetic field, the materials containing the particle act ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.