Electron microdiffraction and energy-dispersive analytical techniques have been used to identify various types of asbolan minerals. In ores of the Liipovskoe and Tyulenova deposits, USSR, Co-Ni asbolan occurs as lamellar aggregates, with ordered Mn4+ and Co-Ni octahedral layers forming two sublattices; molecular H2O occurs between the Co-Ni layers. In Ni asbolan from the central Urals, octahedral Mn4+ and insular Ni layers are aligned along the c axis, the ordered distribution of Ni resulting in the a parameter (5.21 A) of the hexagonal Ni-sublattice being sq root 3 X that (2.83 A) of the Mn4+-sublattice. In Co asbolan from Zaalveld, Thuringia, Co3+ cations occur in tetrahedral coordination with ordered interlayering of Mn4+ octahedral and Co3+ tetrahedral layers. Crystal-chemical data on birnessite, buserite, akhtenskite and vernadite are presented. -R.A.H.