Results of complex mineralogical research of dark micas from plutons with lithium-fluoric granites in the East of Russia – Severny (Chukotka) and Verhneurmijsky (The Far East), proving process existence biotite zinnwalditization are resulted. Use changed biotite as the regional indicator rare metal magmatism is offered.
Zinnwaldite, biotite, pseudomorphose, lithium-fluoric granite, rare metal magmatism, East of Russia