Psilomelane is a mineral that belongs to the oxide group. It is a dark-colored mineral that has a dull luster and is commonly found in manganese deposits. There are several other terms that are often used as synonyms for psilomelane, including black hematite, manganese dioxide, pyrolusite, and wad. The term black hematite refers to psilomelane's dark color and iron content, while manganese dioxide and pyrolusite both refer to psilomelane's chemical composition. The term wad is an old mining term that was used to refer to any black, earthy manganese-bearing material. All of these terms are often used interchangeably with psilomelane in both scientific and industrial contexts.