Wad is an old

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

term for any black

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. I ...

mineral-rich rock in the oxidized zone of various

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...

deposits. Typically closely associated with various

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...

oxides. Specific mineral varieties include

pyrolusite Pyrolusite is a mineral consisting essentially of manganese dioxide ( Mn O2) and is important as an ore of manganese.. It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform ...

, lithiophorite,

nsutite Nsutite is a manganese oxide mineral with formula: ( Mn4+1−xMn2+x O2-2x(O H)2x where x = 0.06-0.07).http://www.webmineral.com/data/Nsutite.shtml Webmineral data It is found in most large manganese deposits and was first discovered in Nsuta, Ghan ...

, takanelite and vernadite.Wad on Mindat.org
/ref> Wad can be considered to be the manganese equivalent to the iron

mineraloid A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amor ...

limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...

References

External links

{{EB1911 poster, Wad Oxide minerals