Seamanite, named for discoverer Arthur E. Seaman, is a rare manganese boron phosphate mineral with formula Mn3[B(OH)4](PO4)(OH)2.

In 1917, Arthur E. Seaman collected a mineral sample from the Chicagon Mine in Iron County, Michigan.

[a] He correctly believed it to be a new mineral species based on a qualitative analysis of its composition by F. B. Wilson.

They cited his career as a professor of geology and mineralogy and his contributions to the field as reasons for the naming.

[6] The type occurrence was found in association with small crystals of calcite, thin coatings of manganese oxide,[6] and fibrous sussexite.