Breyite is a high pressure calcium silicate mineral (CaSiO3) found in diamond inclusions.[3][4] It is the second most abundant inclusion after ferropericlase, for diamonds with a deep Earth origin.[5][4] Its occurrence can also indicate the host diamond's super-deep origin. This mineral is named after German mineralogist, petrologist and geochemist Gerhard P. Brey.
CaSiO3 phase diagram showing Breyite is stable around 3-9 GPa[6]
^Brenker, Frank E.; Nestola, Fabrizio; Brenker, Lion; Peruzzo, Luca; Harris, Jeffrey W. (1 January 2021). "Origin, properties, and structure of breyite: The second most abundant mineral inclusion in super-deep diamonds". American Mineralogist. 106 (1): 38–43. Bibcode:2021AmMin.106...38B. doi:10.2138/am-2020-7513. S2CID231543488.
^Alderton, David; Elias, Scott (2020). Encyclopedia of Geology. Elsevier Science. p. 467. ISBN9780081029091.