Mineral composition of ferromanganese nodules from the Pacific Ocean

The manganese minerals constitutive of ferromanganese nodules retrieved during cruises of the R/V Vityaz wer determined by X-ray diffraction. The analyses were made of well crystallized microscopic areas and several X-ray analyses were made for each nodule. The samples for analyses were selected under a microscope by P. F. Andrushchenko, using reflectivity as a criterion for distinguishing between Todorolite and Birnessite.