Scientists confirm the presence of rare diamond in stony meteorites

Australian and international researchers have used ANSTO’s Australian Synchrotron to confirm the presence of an unusual diamond found in stony meteorites.

The ureilite meteorites contain a rare hexagonal form of diamond, lonsdaleite, that may have been formed shortly after an ancient dwarf planet collided with a large asteroid about 4.5 billion years ago.

The team of scientists from Monash UniversityRMIT UniversityCSIRO, the Australian Synchrotron and Plymouth University confirmed the existence of lonsdaleite and clarified how it was formed in a paper in the Proceedings of the National Academy of Sciences (PNAS) journal. The study was led by geologist Professor Andy Tomkins from Monash University.

Beamline scientists Dr Andrew Langendam and Dr Helen Brand assisted the team with experiments on the powder diffraction beamline.

“Information that indicated the presence of lonsdaleite was gained by other methods but what was needed most was confirmation of lonsdaleite,” explained Dr Langendam.

“Our powder diffraction beamline is able to differentiate complex mineral phases, such as those found in the meteorites.

“X-ray diffraction revealed a series of peaks representing pyroxene, goethite, olivine and lonsdaleite,” he added.

Read more on the ANSTO website

Image: Mineral map highlighting the partial replacement of lonsdaleite by diamond 

Credit: Authors Sequential Lonsdaleite to Diamond Formation in Ureilite Meteorites via In Situ Chemical Fluid/Vapor Deposition PNAS  119 (38) e2208814119