[5] It is the main manganese mineral species at the Earth's surface, and commonly occurs as fine-grained, poorly crystallized aggregates in soils, sediments, grain and rock coatings (e.g., desert varnish), and marine ferromanganese nodules and crusts.

Its precipitation from the oxidation of Mn(II) in oxygenated aqueous solutions is kinetically hindered and slow on mineral surfaces.

Because a solid is overall electrically neutral, birnessite contains foreign cations to balance the net negative charge created by Mn4+ vacancies and heterovalent Mn substitutions.

[18] A natural birnessite crystal may contain only a few layers, and they are often bent and always imperfectly stacked with orientational and translational loss of registry.

[8][23][24][25][26][27][28][29][30] The relative stability of the interlayer cations has been evaluated experimentally[31][32] and theoretically by surface complexation modeling[33] and computational chemistry.

[34][35] Pb2+ has the highest stability at the HBi surface, and the high geochemical affinity of Pb2+ for birnessite probably explains its billion-fold enrichment in marine ferromanganese deposits compared to seawater, which surpasses those of all other elements.

[41] Because of their semiconducting properties, birnessite-type materials are used in a variety of areas, including catalysis and electrochemical energy storage (batteries and pseudocapacitors).