The paper discuss bimetasomatic layers of forearc ophiolite: Sakhalin, Kamchatka, Koryak Range. These layers formed during the mantle diapir uplift at a depth of 30-0,5 km. Temperatures change from 900o to 350oC. Diopside of bimetasomatic layers differ from those of magmatic differences is extremely high (50%) content of wollastonite molecules and high value parameter α (9,761Å) structure of the cell.
Keywords: ophiolites, diaper, bimetasomatic layers, diopside, wollastonite molecule, the structural parameters of the cell.