New diamond harder than ring bling

13 December 2016

An international team has created a harder-than-diamond Lonsdaleite diamond - usually found at the site of meteoric impacts. Unlike cubic diamonds, the hexagonal creation is more likely to be used in manufacturing.

We realised it was something very, very special.
Professor David McKenzie

The University of Sydney has collaborated in an international project including the Australian National University and RMIT to make a diamond predicted to be harder than a jeweller’s diamond and may be useful for cutting through ultra-solid materials on mining sites.  

The team, which included the University of Sydney’s Professor David McKenzie from the Applied Physics Laboratory and ANU PhD student Thomas Shiell, made nano-sized Lonsdaleite.

Lonsdaleite is a hexagonal diamond only found in nature at the site of meteorite impacts such as Canyon Diablo in the United States.

The researchers were able to make the Lonsdaleite in a diamond anvil at 400 degrees Celsius - halving the temperature at which it can be formed in a laboratory. The findings are published in the Nature journal’s “Scientific Reports”.

Corresponding author from the University of Sydney’s School of Physics, Professor David McKenzie, said as part of the research he had been doing the night shift in a United States laboratory when he noticed a little shoulder on the side of a peak.

A diamond in the anvil the scientists used to make the nano-sized Lonsdaleite.

A diamond in the anvil the scientists used to make the nano-sized Lonsdaleite. Image: Jamie Kidston, ANU.

 “It didn’t mean all that much until we examined it later on in Melbourne and in Canberra – and we realised that it was something very, very different,” Professor McKenzie said.

Associate Professor Jodie Bradby from ANU said the hexagonal structure of the diamond’s atoms made it much harder than regular diamonds, which have a cubic structure.

“We’ve been able to make it at the nanoscale and this is exciting because often with these materials ‘smaller is stronger’,” Associate Professor Bradby said.

Co-researcher Professor Dougal McCulloch from RMIT said the collaboration of world-leading experts in the field was essential to the project’s success and “the team utilised state-of-the-art instrumentation”, he said.

Watch how the diamond was discovered

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