nOttrelite(Min) A micaceous mineral occurring in small scales. It is characteristic of certain crystalline schists.
Century Dictionary and Cyclopedia
nottreliteA mineral occurring in small mica-like scales in a schistose rock (ottrelite schist) near Ottrez, in the Ardennes. It is a silicate of aluminium and iron with some manganese. The ottrelite group includes ottrelite proper and several related minerals, as chloritoid, sismondine, and masonite; they belong to the group of so-called brittle micas.