SHIGAITE AND RHODOCHROSITE COMBO, KALAHARI MANGANESE FIELDS, KURUMAN, SOUTH-AFRICA (small cabinet)

Shigaite is a mineral characterized by the formula NaAl3(Mn2+)6(SO4)2(OH)18·12H2O, commonly found in the form of small hexagonal crystals or thin layers. It was first identified in 1985 in Shiga Prefecture, Japan, which is reflected in its name. A major revision of its chemical formula occurred in 1996, revealing sodium as a previously unrecognized component.