Cliftonite in Meteorites: A Proposed Origin

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Science  12 May 1967:
Vol. 156, Issue 3776, pp. 819-820
DOI: 10.1126/science.156.3776.819


Cliftonite, a polycrystalline aggregate of graphite with cubic morphology, is known in ten meteorites. Some workers have considered it to be a pseudomorph after diamond, and have used the proposed diamond ancestry as evidence of a meteoritic parent body of at least lunar dimensions.We have synthesized cliftonite in Fe-Ni-C alloys in vacuumn, as a product of decomposition of cohenite [(Fe, Ni)3C]. We therefore suggest that a high pressure origin is unnecessary for meteorites which contain cliftonite, and that these meteorites were formed at low pressures. This concluision is in agreement with other recent evidence.