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brownmillerite

n. (context mineral English) A mineral with the chemical formula Ca2(Al,Fe+++)2O5, found in metamorphosed limestone.

Wikipedia
Brownmillerite

Brownmillerite is a rare oxide mineral with chemical formula Ca(Al,Fe)O. It is named for Lorrin Thomas Brownmiller (1902–1990), chief chemist of the Alpha Portland Cement Company, Easton, Pennsylvania.