a. An earthy, dark brown to black mineral material consisting chiefly of an
impure mixture of manganese oxides and oxyhydroxides with variable amounts of
copper, cobalt, and iron oxides and oxyhydroxides and silica plus 10% to 20%
adsorbed water. It is commonly soft (soiling hands), but may be hard and
compact, and has a low density. Wad results from the decomposition of other
manganese minerals and accumulates in marshy areas or other zones of
ground-water emission where it is an ore of manganese. See also:
asbolan earthy manganese; manganese hydrate.
b. A general term for massive,
fine-grained manganese oxides and oxyhydroxides of low density, but not further
identified.
c. In drilling, a term applied to rock cuttings that tend to ball
and adhere to drill-string equipment and borehole walls in lumps. Long
Source:
Dictionary of Mining, Mineral, and Related Terms
