Innsbruckite

Where it forms, where it's found

Geological setting: interface between a serpentinite body and cherts
Type locality: Innsbruckite occurrence
Staffelsee
Navis
Innsbruck-Land District
Tyrol
Austria
47.1408°, 11.6253°

2recorded occurrences

Source · OpenStreetMap

Physical

Hardness: 1Talc
2Gypsum
3Calcite
4Fluorite
5Apatite
6Orthoclase
7Quartz
8Topaz
9Corundum
10Diamond
Colour: Pale brownish (no colour stated in original description · inferred from similarity to bementite) · nearly colourless in transmitted light (thin section).
Density: 3.216 g/cm³

Optical

Optical type: Biaxial (-)
Notes: Gladstone-Dale average refractive index of 1.678 was calculated

Crystallography

Crystal system: Monoclinic
Space group: Cm
Cell parameters: a = 17.276(2) Å · b = 35.957(5) Å · c = 7.2560(8) Å
Cell angles: β = 91.359(7) °
Ratio a:b:c: 1 : 2.081 : 0.420
Unit cell volume: 4506.1 Å³
Z: 2
Type-locality form: thin platy crystals

Crystal structure

Chemical composition

Constituent elements: Mass composition breakdown
Element Atoms At. mass g/mol Mass g/mol Mass share
25MnManganese Manganese 33 54.938 1812.954
41.53%
8OOxygen Oxygen 108 15.999 1727.892
39.58%
14SiSilicon Silicon 28 28.085 786.380
18.01%
1HHydrogen Hydrogen 38 1.008 38.304
0.88%
Total 4365.530 100.00%
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
25MnManganese	Manganese	33	54.938	1812.954	41.53%
8OOxygen	Oxygen	108	15.999	1727.892	39.58%
14SiSilicon	Silicon	28	28.085	786.380	18.01%
1HHydrogen	Hydrogen	38	1.008	38.304	0.88%
	Total	4365.530	100.00%

Synonyms

IMA2013-038
Innsbruckiet
Unnamed (Mn Silicate-Hydroxide)

In other languages

German: IMA 2013-038 · Innsbruckit
Italian: innsbruckite

Classification

Strunz

10th ed.

9.EE.07

9SilicatesClass
9.EPhyllosilicatesDivision
9.EESingle tetrahedral nets of 6-membered rings connected by octahedral nets or octahedral bandsGroup
9.EE.07InnsbruckiteSpecies

Literature, links & citation

Citations

2013Krüger, H., Tropper, P., Haefeker, U., Tribus M., Kahlenberg, V., Wikete, C., Fuchs, M.R., and Olieric, V. (2013) Innsbruckite, Mn33(Si2O5)14(OH)38: a new manganese phyllosilicate mineral from the Tyrol. MinPet2013, Meeting of the Austrian Mineralogical Society, Mitteilungen der Österreichischen Mineralogischen Gesellschaft 159: 85 (Abstract).
2013tirol.orf.at (n.d.) http://tirol.orf.at/news/stories/2612087/
2013Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No.17. Mineralogical Magazine, 77 (7) 2997-3005 doi:10.1180/minmag.2013.077.7.09DOI: 10.1180/minmag.2013.077.7.09
2014Tropper, P., Kahlenberg, V., and Krüger, H. (2014) Innsbruckit, ein neues Mn-Schichtsilikat aus der Wattener Lizum (Bezirk Innsbruck-Land, Tirol). Der Steirische Mineralog 28, 60.
2014Krüger, Hannes, Tropper, Peter, Haefeker, Udo, Kaindl, Reinhard, Tribus, Martina, Kahlenberg, Volker, Wikete, Christoph, Fuchs, Martin R., Olieric, Vincent (2014) Innsbruckite, Mn₃₃(Si₂O₅)₁₄(OH)₃₈ – a new mineral from the Tyrol, Austria. Mineralogical Magazine, 78 (7) 1613-1627 doi:10.1180/minmag.2014.078.7.06DOI: 10.1180/minmag.2014.078.7.06

Cite this entry

@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Innsbruckite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/innsbruckite-43903},
  note      = {Accessed 2026-05-11}
}