Rare ‘Lonsdaleite’ meteorite diamonds could end up on construction site

A rare type of diamond called lonsdaleite may have formed in meteorites in the mantle of a dwarf planet after a catastrophic collision. Additionally, diamond could be instrumental in making machine parts stronger.

The news comes from RMIT University and CSIRO, in collaboration with Monash University, the Australian Synchrotron and the University of Plymouth.

The research team found evidence that lonsdaleite, a rare type of diamond, formed in meteorites from hexagonally shaped dwarf planets. It is 58% stronger than an ordinary diamond.

Electron microscopy techniques have been used to analyze slices of meteorites, trying to categorize the formation of lonsdaleite and regular diamonds.

“We propose that the lonsdaleite in the meteorites formed from supercritical fluid at high temperature and moderate pressures, almost perfectly preserving the textures of pre-existing graphite,” said Professor Andy Tomkins of Monash University.

“Later, the lonsdaleite was partially replaced by diamond as the environment cooled and the pressure decreased.”

Although lonsdaleite can be tougher than regular diamonds, the largest crystallites of lonsdaleite are only one micron in size.

Professor Andy Tomkins (left) of Monash University with RMIT University PhD student Alan Salek and a ureilite meteor sample. Image: RMIT University

“There is strong evidence that there is a newly discovered formation process for lonsdaleite and ordinary diamond, which resembles a supercritical chemical vapor deposition process that took place in these space rocks, probably on the dwarf planet shortly after a catastrophic collision. [with an asteroid]said Professor Dougal McCulloch, director of the RMIT Microscopy and Microanalysis Facility.

In short, this study is important because it confirms that lonsdaleite can form in nature, indicating that it could be produced synthetically.

Why would you want to produce it synthetically? Well, the rare type of diamond could be used in machinery to improve component strength.

Diamonds are currently used in machine components, especially in tools like drills and saws, but having a more durable material could improve the longevity of devices and tools.

“If something that’s harder than diamond can be made easily, that’s something the industry would want to know,” added CSIRO scientist Colin MacRae.

MacRae added that these discoveries could have big implications for mining.

Heck yeah, we love space diamonds.

You can read the results in PNAS, or read the press release from RMIT University or CSIRO.