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Meteorite shower

Powerful synchrotron light confirms 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 University, RMIT University, CSIRO, 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.

pnas.2208814119fig03
Mineral maps highlighting the partial replacement of lonsdaleite by diamond  Copyright: Authors Sequential Lonsdaleite to Diamond Formation in Ureilite Meteorites via In Situ Chemical Fluid/Vapor Deposition PNAS  119 (38) e2208814119

“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.

“Because our team has worked extensively with meteorites, we were able to distinguish the lonsdaleite from diamond and from the other minerals despite their smeared peaks, created by structural variability.”

The research team suggested that the unusual structure of lonsdaleite could help inform new manufacturing techniques for ultra-hard materials in mining applications. 

Read more on the RMIT website

DOI: https://doi.org/10.1073/pnas.2208814119

Scientists

Prof Andrew Tomkins

Prof Andrew Tomkins (Monash)

Dr Andrew Langendam

Dr Andrew Langendam

Dr Helen Brand

Dr Helen Brand