Making diamonds in nature requires an extremely long time to the tune of billions of years under vast amounts of pressure and extremely high temperatures. A group of researchers at the Australian National University and RMIT University have made two types of diamonds at room temperature. One of the diamonds the team created is the typical diamond type found in rings, and the other diamond is called Lonsdaleite.
Lonsdaleite is found in nature at meteorite impact sites such as Canyon Diablo in the US. Creating diamonds in nature is typically done deep inside the Earth at a depth of about 150 kilometers where pressure is high enough and temperatures are above 1000 degrees Celsius. The researcher’s unexpected discovery shows that both types of diamond can form at room temperature under high pressure.
The pressure the team used to create diamonds was equivalent to 640 African elephants standing on the tip of a ballet shoe. The team says at high pressures, the carbon experiences something called “shear,” which is a twisting or sliding force. They believe shear allows carbon atoms to move into place and form regular diamond or Lonsdaleite.
Advanced electron microscope techniques allowed researchers to capture solid and intact slices from the experimental samples creating snapshots of how the two types of diamond form. Regular diamonds only form in the middle of the Lonsdaleite veins using the team’s new method.
Lonsdaleite is predicted to be 58 percent harder than regular diamond, thanks to a different crystal structure. This type of diamond has the potential to be used for cutting through ultra-solid materials at mining sites. Lonsdaleite is rare and very useful. Creating more of it is the long-term aim of the research.