Wad is an old mining term for any black manganese oxide or hydroxide mineral-rich rock in the oxidized zone of various ore deposits. Typically closely associated with various iron oxides. Specific mineral varieties include pyrolusite, lithiophorite, nsutite, takanelite and vernadite.[1] Wad can be considered to be the manganese equivalent to the iron mineraloid limonite.
References
- Palache, Charles; Berman, Harry; Frondel, Clifford (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides (7th, revised and enlarged ed.), New York: John Wiley and Sons, Inc., pp. 566–567