Formula: Ba(Mn4+6Mn3+2)O16

Species: Oxides

Colour: Silvery-grey to greyish black, black

Lustre: Metallic

Hardness: 4 – 6

Specific Gravity: 4.95

Crystal System: Monoclinic

Member of: Coronadite Group > Hollandite Supergroup

Name: Named in honor of Sir Thomas Henry Holland (1868–1947), geologist and educational administrator. He was Director of the Geological Survey of India. He also held administrative positions at the Imperial College London and the University of Edinburgh.

Type Locality: Gowari Wadhona Mine, Chhindwara District, Jabalpur Division, Madhya Pradesh, India

Isostructural with: Coronadite, Cryptomelane, Manjiroite, Strontiomelane

In 2012, the IMA revised the nomenclature of the Hollandite Supergroup . Hollandite is now redefined as the (more widespread) Ba-Mn3+ end-member of the coronadite group; concurrently, type hollandite is redefined as ferrihollandite, a new name to denote the Ba-Fe3+ end-member. Visually indistinguishable from cryptomelane and several other manganese oxide minerals. Chemically similar to romanèchite.