According to petrologic analysis of 18 samples of altered rock, phlogopite rock, with regard to its B 2O 3 content, it is generally restricted to the outside of the ore bed, having certain ties with the boron minerlization while no ties are found in altered rock of the same type associated with veins of diorite porphyrite.

The biotitites of Ance and Vazeilles are included in dack factes of finite of Margeride in cental massif of France,their size are of about ten meters.