HPHT-Treated Impact Diamonds from the Popigai Crater (Siberian Craton): XRD and Raman Spectroscopy Evidence

HPHT-Treated Impact Diamonds from the Popigai Crater (Siberian Craton): XRD and Raman Spectroscopy Evidence

Phase change and graphitization of diamonds from the Popigai impact crater (Krasnoyarsk Territory, Siberian platform, Russia) exposed to high-pressure high-temperature (HPHT) conditions of 5.5 GPa and 2000–2200 °C are studied by Raman spectroscopy and X-ray diffractometry (XRD). Light-color diamonds...

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Bibliographic Details
Published in:Minerals (Basel) Vol. 13; no. 2; p. 154
Main Authors: Anatoly Chepurov, Sergey Goryainov, Sergey Gromilov, Egor Zhimulev, Valeriy Sonin, Aleksey Chepurov, Zakhar Karpovich, Valentin Afanasiev, Nikolay Pokhilenko
Format: Journal Article
Language:English
Published: MDPI AG 01-01-2023
Subjects:
graphitization
high-pressure high-temperature (HPHT) experiment
impact diamond
lonsdaleite
Raman spectroscopy
XRD
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Summary:Phase change and graphitization of diamonds from the Popigai impact crater (Krasnoyarsk Territory, Siberian platform, Russia) exposed to high-pressure high-temperature (HPHT) conditions of 5.5 GPa and 2000–2200 °C are studied by Raman spectroscopy and X-ray diffractometry (XRD). Light-color diamonds of type 1, free from inclusions, with 0 to 10 % lonsdaleite, are more resistant to HPHT effects than dark diamonds of type 2 rich in lonsdaleite and graphite. The lonsdaleite/diamond ratios in lonsdaleite-bearing impact diamonds become smaller upon annealing, possibly because lonsdaleite transforms to cubic diamond simultaneously with graphitization. Therefore, lonsdaleite is more likely a structure defect in diamond than a separate hexagonal phase.
ISSN:2075-163X
DOI:10.3390/min13020154