The formation of diamonds in the natural world takes billions of years, huge amounts of pressure and ultra-hot temperatures.
Now an international team of scientists, led by the Australian National University and RMIT, have managed to defy nature by creating diamonds in a lab in just a few minutes.
The team made two types of diamonds: the kind found on an engagement ring, and another type of diamond called lonsdaleite, which is found in nature at the site of meteorite impacts such as Canyon Diablo in the US.
Lead researcher and ANU Professor Jodie Bradby said lonsdaleite, which is 58% harder than regular diamonds, has the potential to be used for cutting through ultra-solid materials on mining sites.
“Creating more of this rare but super useful diamond is the long-term aim of this work,” Prof Bradby said.
The team, including former ANU PhD scholar Tom Shiell – who is now at the Carnegie Institution for Science – previously created lonsdaleite in the lab only at high temperatures.
This new, unexpected discovery shows both lonsdaleite and regular diamond can also form at normal room temperatures by applying high pressure—equivalent to 640 African elephants on the tip of a ballet shoe.
Prof Bradby said the key was in how the pressure was applied.
“As well as very high pressures, we allow the carbon to also experience something called ‘shear’, which is like a twisting or sliding force,” she said.
“We think this allows the carbon atoms to move into place and form lonsdaleite and regular diamond.”
Co-lead researcher Professor Dougal McCulloch and his team at RMIT used advanced electron microscopy techniques to capture solid and intact slices from the experimental samples to create snapshots of how the two types of diamonds formed.
“Our pictures showed the regular diamonds only form in the middle of these Lonsdaleite veins under this new method developed by our cross-institutional team,” he said.
“Seeing these little ‘rivers’ of Lonsdaleite and regular diamond for the first time was just amazing and really helps us understand how they might form.”
The team, which involved University of Sydney and Oak Ridge National Laboratory in the US, have published the research findings in the journal Small.