romanechite

Romanechite is a complex hydrated manganese oxide mineral with the chemical formula (Ba,H2O)2(Mn4+,Mn2+)5O10·nH2O. It belongs to the group of plus manganese oxide minerals and is notable for its layered, tabular crystal habit. Romanechite is often characterized by its black to brownish-black coloration and a generally opaque appearance.

This mineral is commonly found in manganese-rich ore deposits and forms as a secondary mineral through the oxidation of primary manganese ores. It frequently occurs in association with other manganese oxides such as pyrolusite, wad, and psilomelane. Romanechite's structure consists of layers of manganese-oxygen octahedra, interlayered with barium and water molecules, giving rise to its hydrated form.

Romanechite is of interest primarily for its economic value as a source of manganese, which is essential for steel production and various industrial applications. Its physical properties, such as high specific gravity and metallic luster, aid in its identification. The mineral typically appears as masses or crusts on manganese ore bodies.

While romanechite itself is not extensively used commercially, its presence can indicate manganese deposits that are economically viable for mining. Due to its mineralogical complexity, romanechite is also studied for insights into mineral formation processes and the geochemical behavior of manganese in Earth's crust.