Phyllosilicate - Monoclinic - Mica group member. Ordinary (True or Common) Mica - Trioctahderal. Contains Li, Al, Mn2+ in the (M) octahedral sites with F>OH in the (A) position. Mindat places K & Rb in the Interlayer sites.
Rare worldwide with only in two in the USA, originally described from Japan. According to Bernard & Hyrsl, occurs in Na-Li rich pegmatites in Czech Republic, and Japan and is typically purple to pink.