Manganosite is a rare mineral composed of manganese(II) oxide

Manganese(II) oxide

Manganese oxide is the inorganic compound with formula MnO. MnO is a basic oxide that is insoluble in water but dissolves in acids, forming manganese salts.-Preparation and occurrence:...

 MnO. It was first described in 1817 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

. It has also been reported from Langban and Nordmark, Sweden

Nordmark, Sweden

Nordmark is a locality situated in Filipstad Municipality, Värmland County, Sweden with 234 inhabitants in 2005....

 and at Franklin Furnace, New Jersey

Franklin Furnace

Franklin Furnace, also known as the Franklin Mine, is a famous mineral location for rare zinc, iron, manganese minerals in old mines in Franklin, New Jersey, USA. This locale produced more species of minerals and more different fluorescent minerals than any other location...

. It also occurs in Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, Kyrgyzstan

Kyrgyzstan

Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...

 and Burkina Faso

Burkina Faso

Burkina Faso – also known by its short-form name Burkina – is a landlocked country in west Africa. It is surrounded by six countries: Mali to the north, Niger to the east, Benin to the southeast, Togo and Ghana to the south, and Côte d'Ivoire to the southwest.Its size is with an estimated...

.

It occurs in manganese nodule

Manganese nodule

Polymetallic nodules, also called manganese nodules, are rock concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. The core may be microscopically small and is sometimes completely transformed into manganese minerals by crystallization...

s. It also occurs as alteration of manganese minerals such as rhodocrosite during low oxygen metamorphism

Metamorphism

Metamorphism is the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Mineralogical, chemical and crystallographic changes can occur during this process...

 and metasomatism

Metasomatism

Metasomatism is the chemical alteration of a rock by hydrothermal and other fluids.Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source. In the igneous environment, metasomatism creates skarns, greisen, and may affect hornfels in the contact...