Outline and Problems of Studies on the Manganese Dioxide Minerals from Japan

Naturally occurring seventeen manganese dioxide minerals, cryptomelane (ishiganeite), hollandite, manjiroite, cororadite, pyrolusite, nsutite (yokosukaite), ramsdellite, birnessite, ranciéite, takanelite, todorokite, lithiophorite, psilomelane, chalcophanite, hydrohetaerolite, auroite and amorphous manganese dioxide mineral, from Japan were briefly reviewed from the stantpoints of descriptive mineralogy, together with the relation between the terrestrial manganese dioxide minerals and the composition of manganese nodules.