Manganese(IV) minerals

Pyrolusite is a mineral consisting essentially of manganese dioxide (MnO2) 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 crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers. The specific gravity is about 4.8. Its name is from the Greek for fire and to wash, in reference to its use as a way to remove tints from glass. thumb|Acicular radiating pyrolusite

Brownleeite is a silicide mineral with chemical formula MnSi. It was discovered by researchers of the Johnson Space Center in Houston in April 2003 while analyzing the Pi Puppid particle shower of the comet 26P/Grigg-Skjellerup. The only other known natural manganese silicide is mavlyanovite, Mn5Si3.

Ramsdellite (Mn4+O2) is an orthorhombic manganese dioxide mineral. It is relatively uncommon, and is usually found in deposits containing other manganese oxide crystals.

Akhtenskite is a manganese oxide mineral with the chemical formula of MnO2 (or: ε-Mn4+O2) that was named after the Akhtensk deposit in Russia, where it was first discovered and noted in 1979. It can be found in the Akhtensk brown ironstone deposit, in the southern Ural Mountains, on Mt. Zarod, on the Sikhote-Alin Mountains, and in the Primorskiy Krai, all in Russia.