Diamonds take billions of years to form at a depth of nearly 150 km below the earth’s surface, but scientists are now able to create diamonds in just minutes in the laboratory.
This research team includes scientists from the Australian National University (ANU) and RMIT University. They used a “diamond anvil” – a high-pressure compression device that presses carbon crystals into both regular and Lonsdaleite hexagonal diamonds at room temperature. The team says the pressure generates up to 100 GPa, which is equivalent to 640 African elephants standing on the toe of ballet shoes.
In the past, this team has also created diamonds in the lab, but at high temperatures. This time, they used pressure at room temperature, says physicist Jodie Bradby: “We’ve put carbon through a state called ‘shear force’ – like a torsion or shear force. We think that’s the case. this allows the carbon atoms to move into the right place, creating both Lonsdaleite and regular diamonds… We simply press the material together at extreme pressure. This process takes place in just a few minutes.”
Study co-author Professor Dougal McCullock (right) and the team at RMIT used an electron microscope to tomography this artificial diamond sample and said: “The images we captured show that Conventional diamonds form only in between the veins of Lonsdaleite diamonds with this high pressure fabrication method.This is the first time we have seen the “rivers” of Lonsdaleite and regular diamonds. From here we will be able to better understand how the two types of diamonds are formed.”
The researchers hope the discovery will help them develop super-hard diamonds for industrial use. Physicist Bradby emphasizes: “Any process that occurs at room temperature is easier and cheaper to do than processes that have to be handled at temperatures up to hundreds or thousands of degrees. However, I do not thinking there will be cheap diamonds on wedding rings eventually, but the Lonsdaleite diamonds we make can become a miner’s best friend, saving them from having to replace their drill bits frequently and expensively. again.”
Lonsdaleite is named after Dame Kathleen Lonsdale – the famous Irish crystallographer, the first woman to be elected a member of the Royal Society of Great Britain. She is best known for her work demonstrating the flat benzene ring using X-ray diffraction in 1929. Lonsdaleite diamonds are known as hexagonal diamonds to reflect its crystal structure and, in nature, it formed when graphite-containing objects crashed to Earth. The extreme heat and pressure created by the collision caused the graphite to turn into diamond but retain the graphite’s hexagonal lattice structure. Lonsdaleite diamonds have actually been synthesized in the laboratory since 1966 by compressing and bringing graphite to high temperatures at static pressure or by explosions. It is also produced by chemical vapor deposition but this is the first time it has been produced at room temperature.