Bunnoite

Where it forms, where it's found

Geological setting: Metasedimentary Fe-Mn ore.
Type locality: Kamoyama mine
Ino
Agawa District
Kochi Prefecture
Japan
33.5567°, 133.4247°

1recorded occurrences

Source · OpenStreetMap

Crystallography

Crystal system: Triclinic
Space group: #2
Cell parameters: a = 7.521(5) Å · b = 10.008(8) Å · c = 12.048(2) Å
Cell angles: α = 70.46(5) ° · β = 84.05(6) ° · γ = 68.31(6) °
Ratio a:b:c: 1 : 1.331 : 1.602

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
8OOxygen Oxygen 21 15.999 335.979
38.88%
25MnManganese Manganese 6 54.938 329.628
38.15%
14SiSilicon Silicon 6 28.085 168.510
19.50%
13AlAluminium Aluminium 1 26.982 26.982
3.12%
1HHydrogen Hydrogen 3 1.008 3.024
0.35%
Total 864.123 100.00%
Mass share = atoms × atomic mass ÷ molar mass × 100
From IMA formula

Mass composition breakdown
Element	Atoms	At. mass g/mol	Mass g/mol	Mass share
8OOxygen	Oxygen	21	15.999	335.979	38.88%
25MnManganese	Manganese	6	54.938	329.628	38.15%
14SiSilicon	Silicon	6	28.085	168.510	19.50%
13AlAluminium	Aluminium	1	26.982	26.982	3.12%
1HHydrogen	Hydrogen	3	1.008	3.024	0.35%
	Total	864.123	100.00%

Synonyms

Bunnoiet
IMA2014-054

In other languages

German: Bunnoit · IMA 2014-054
Italian: bunnoite
Japanese: 豊石

Classification

Strunz

10th ed.

9.BH

9SilicatesClass
9.BSorosilicatesDivision
9.BHSorosilicates with Si₃O₁₀, Si₄O₁₁, etc. anions; cations in tetrahedral [4] and greater coordinationGroup
9.BHBunnoiteSpecies

Literature, links & citation

Citations

2014Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2014) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC), CNMNC Newsletter No. 22. Mineralogical Magazine, 78 (5) 1241-1248 doi:10.1180/minmag.2014.078.5.10DOI: 10.1180/minmag.2014.078.5.10
2016Nishio-Hamane, Daisuke, Momma, Koichi, Miyawaki, Ritsuro, Minakawa, Tetsuo (2016) Bunnoite, a new hydrous manganese aluminosilicate from Kamo Mountain, Kochi prefecture, Japan. Mineralogy and Petrology, 110 (6) 917-926 doi:10.1007/s00710-016-0454-2DOI: 10.1007/s00710-016-0454-2
2017(2017) Bunnoite. Handbook of Mineralogy. Mineralogical Society of America

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Bunnoite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/bunnoite-46195},
  note      = {Accessed 2026-05-11}
}