Shigaite is a mineral with formula NaAl3(Mn2+)6(SO4)2(OH)18·12H2O that typically occurs as small, hexagonal crystals or thin coatings.

Shigaite occurs as hexagonal tabular crystals up to 2 cm (0.79 in) in size or as thin films and coatings.

[5] Shigaite occurs in metamorphosed deposits of manganese ore[5] and is the Mn2+ analogue of motukoreaite.

[3] The original study, published in the journal Neues Jahrbuch für Mineralogie, Monatshefte,[1] identified the formula as Al4Mn7(SO4)2(OH)22·8H2O.

[8] As of 2012[update], shigaite is known from the following sites:[3] The type material is housed in the National Museum of Natural History in Washington, D.C. as sample 122089.