Manganese ores are found in metamorphic rocks or sedimentary deposits. Pyrolusite is the main ore mineral for manganese. Manganese combines easily with air and water and is therefore a reactive element frequently found in nodules on the sea floor.

It is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron.
Manganese is a metal with important industrial metal alloy uses, particularly in stainless steels