Ilsemannite
A valid IMA mineral species - grandfathered - questionable
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About Ilsemannite
Johann C. Ilsemann
Formula:
Mo3O8 · nH2O
Colour:
Black, blue-black, or blue; turns blue on exposure
Crystal System:
Amorphous
Name:
After Johann Christoph Ilsemann (1727-1822), a former Mining Commissioner at Clausthal, Harz, who published an early study of molybdenite (1787).
Type Locality:
Note that there are numerous different and very complex heterovalent molybdenum oxide molecules forming amorphous blue substances. Most likely the "ilsemannites" at different localities, formed under different conditions, are not the same compound and may even be mixtures of several different compounds. Consequently "ilsemannite" does not really deserve mineral species status and may eventually turn out to be several different species when technology advances to when we can better characterize very thin amorphous films.
Ilsemannite was once thought to be responsible for the blue colour of "blue waters" of the Idaho Springs area, known to Indians, but it was later shown that rather more complex, up-to-200-metal-atoms compounds may be the cause.
See also the visually similar mourite.
Ilsemannite was once thought to be responsible for the blue colour of "blue waters" of the Idaho Springs area, known to Indians, but it was later shown that rather more complex, up-to-200-metal-atoms compounds may be the cause.
See also the visually similar mourite.
Unique Identifiers
Mindat ID:
2015
Long-form identifier:
mindat:1:1:2015:8
IMA Classification of Ilsemannite
Approved, 'Grandfathered' (first described prior to 1959), Questionable
IMA Formula:
Mo4+Mo6+2O8·nH2O
First published:
1871
Classification of Ilsemannite
4.FJ.15
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
J : Hydroxides with H2O +- (OH); corner-sharing octahedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
J : Hydroxides with H2O +- (OH); corner-sharing octahedra
4.6.3.1
4 : SIMPLE OXIDES
6 : Miscellaneous
4 : SIMPLE OXIDES
6 : Miscellaneous
7.15.4
7 : Oxides and Hydroxides
15 : Oxides of Mo and W
7 : Oxides and Hydroxides
15 : Oxides of Mo and W
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ils | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Ilsemannite
Transparency:
Translucent
Colour:
Black, blue-black, or blue; turns blue on exposure
Streak:
Pale blue
Chemistry of Ilsemannite
Mindat Formula:
Mo3O8 · nH2O
Elements listed:
Crystallography of Ilsemannite
Crystal System:
Amorphous
Morphology:
Earthy masses or crusts; as a stain or disseminated pigment.
Comment:
Amorphous. Point Group: n.d. Space Group: n.d. Z = n.d.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47e : [Vanadates, chromates, manganates] | |
| 47h : [Near-surface oxidized, dehydrated minerals] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Ilsemannite
Synonyms of Ilsemannite
Other Language Names for Ilsemannite
Dutch:Ilsemanniet
German:Ilsemannit
Molybdänblau
Molybdänblau
Simplified Chinese:蓝钼矿
Spanish:Ilsemannita
Traditional Chinese:蓝鉬矿
Common Associates
Associations Based on Photo Data:
| 20 photos of Ilsemannite associated with Jordisite | MoS2 |
| 9 photos of Ilsemannite associated with Tugarinovite | MoO2 |
| 6 photos of Ilsemannite associated with Halotrichite | Fe2+Al2(SO4)4 · 22H2O |
| 6 photos of Ilsemannite associated with Molybdenite | MoS2 |
| 6 photos of Ilsemannite associated with Anhydrite | CaSO4 |
| 5 photos of Ilsemannite associated with Alunogen | Al2(SO4)3 · 17H2O |
| 4 photos of Ilsemannite associated with Raydemarkite | MoO3 · H2O |
| 4 photos of Ilsemannite associated with Chistyakovaite | Al(UO2)2(AsO4)2(F,OH) · 6.5H2O |
| 4 photos of Ilsemannite associated with Mourite | UMo5O12(OH)10 |
| 4 photos of Ilsemannite associated with Iriginite | (UO2)Mo2O7 · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 4.FJ. | Raydemarkite | MoO3 · H2O |
| 4.FJ.05 | Sidwillite | MoO3 · 2H2O |
| 4.FJ.05 | Meymacite | WO3 · 2H2O |
| 4.FJ.10 | Tungstite | WO3 · H2O |
| 4.FJ.15 | Hydrotungstite | WO3 · 2H2O |
Other Information
Notes:
Solublizes in H2O giving a deep molybdenum-blue solution.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Ilsemannite
mindat.org URL:
https://www.mindat.org/min-2015.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Ilsemannite
Reference List:
Localities for Ilsemannite
Showing 166 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Argentina | |
| Perelló et al. (2023) |
Australia | |
| Hurtig et al. (2014) |
| |
| Bottrill et al. (2008) |
Austria (TL) | |
| Am Min 36 (1951) +1 other reference |
| Kostelka (1956) | |
| Gerhard Niedermayr | |
| Exel (1993) |
| Hanneberg et al. (2009) +1 other reference |
Brazil | |
| Waber et al. (1992) +1 other reference |
Chile | |
| Lohmeier et al. (2025) |
| Lohmeier et al. (2022) | |
China | |
| Min et al. (2002) |
| Dahlkamp (2009) |
| Guangyin Shen (2011) | |
| Liu et al. (2022) |
| Dahlkamp (2009) |
| Dahlkamp (2009) |
| Dahlkamp (2009) |
Czech Republic | |
| Jirásek (2001) |
| Scharm +7 other references |
| |
| Sejkora +1 other reference |
Gabon | |
| Geffroy et al. (1960) |
Germany | |
| Walenta (1992) |
| Hegemann (1949) +1 other reference |
| Möhn et al. (07/2020) |
| Wittern (2001) |
| Wittern (2001) |
| Jahn (1999) |
| Kolitsch et al. (1997) +1 other reference |
| Wittern (2001) |
| Witzke et al. (1998) |
Guatemala | |
| Stoiber et al. (1974) +1 other reference |
Indonesia | |
| Nitta et al. (2006) | |
| Imants Kavalieros (1994) |
Japan | |
| Africano et al. (2002) |
| Africano et al. (2002) | |
| Field observations | |
| Africano et al. (2002) +1 other reference | |
Mexico | |
| Panczner (1987) |
| Braith et al. (2001) |
Romania | |
| Szakáll (2002) |
Russia | |
| Yu. Engalychev (2019) |
| Nitta et al. (2006) +2 other references |
| Vergasova et al. (1977) +1 other reference |
| Kiseleva et al. (2008) |
| Pavel M. Kartashov (n.d.) |
| Pavel M. Kartashov (n.d.) | |
Slovenia | |
| Rečnik (2010) | |
| Terzic () | |
South Africa | |
| Cairncross et al. (1995) |
Switzerland | |
| EDX & XRD (amorphous) |
Tajikistan | |
| D.I.Belakovskiy data |
| Pavel M. Kartashov (n.d.) +2 other references |
UK | |
| Raymond (1959) +1 other reference |
USA | |
| Witkind (1963) +1 other reference |
| Graeme (1981) |
| Anthony et al. (1995) |
| Bollin et al. (1958) +1 other reference |
| Bollin & Kerr (1958) +1 other reference | |
| Scarborough (1981) | |
| Anthony et al. (1995) |
| Anthony et al. (1995) | |
| Scarborough (1981) | |
| Gornitz (2004) |
| Scarborough (1981) |
| Petersen et al. (1959) +1 other reference | |
| Palache et al. (1951) +1 other reference |
| Page et al. (1956) +2 other references |
| Troxel et al. (1962) +2 other references |
| Troxel et al. (1962) +2 other references | |
| Cook (1922) +3 other references |
| - (2005) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Dings et al. (1957) |
| Dings et al. (1957) | |
| Eckel et al. (1997) |
| - (2005) |
| - (2005) | |
| Eckel et al. (1997) | |
| Eckel et al. (1997) | |
| - (2005) |
| Page et al. (1956) +3 other references |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Carnein et al. (2005) |
| Barrick Gold Corporation |
| NBMG Bull 78 Geology and Mineral ... +2 other references |
| NBMG Bull 78 Geology and Mineral ... +2 other references | |
| Schilling (1979) +1 other reference | |
| - (2005) | |
| Barrick Gold Corporation | |
| Newmont Mining Corporation |
| Schilling (1979) +1 other reference |
| Castor et al. (2004) | |
| - (2005) | |
| - (2005) | |
| Barrick Gold Corporation | |
| - (2005) | |
| Castor et al. (2004) |
| Schilling (1979) |
| Schilling (1979) +1 other reference |
| - (2005) |
| Ken Coleman Collection |
| NBMG Bull 70 Geology and Mineral ... +2 other references |
| Schilling (1979) +1 other reference | |
| Northrop et al. (1996) |
| Ramon S. DeMark +4 other references |
| NMBMMR Memoir 15 Geology and Technology ... |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| - (2005) | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| - (2005) | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| - (2005) |
| Nevada Bureau of Mines and Geology NBMG ... |
| Smith et al. (2000) |
| Roberts et al. (1965) | |
| Roberts et al. (1965) |
| Smith et al. (2000) |
| Smith (1991) +1 other reference |
| Smith (1991) |
| - (2005) | |
| - (2005) | |
| MINERALS OF THE KARNES URANIUM ... | |
| - (2005) |
| Luetcke (n.d.) |
| Young et al. (1960) |
| Bullock (1981) |
| Collection of Philip Bluemner |
| Page et al. (1956) +2 other references |
| Bullock (1981) | |
| Bullock (1981) | |
| Bullock (1981) |
| Mccaskey +1 other reference |
| Bullock (1981) |
| Bullock (1981) | |
| Bullock (1981) |
| Bullock (1981) | |
| - (2005) | |
| USGS Bull 1125 |
| Olds et al. (2023) |
| Bullock (1981) +1 other reference | |
| USGS TEI #514 +3 other references | |
| - (2005) |
| - (2005) |
| Bullock (1981) | |
| - (2005) | |
| Hausel et al. (2001) |
| - (2005) |
| www.excaliburmineral.com +5 other references | |
| - (2005) | |
| - (2005) |
Uzbekistan | |
| Ishbobaev et al. (2023) |
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Barbora adit, Knöttel area, Krupka, Teplice District, Ústí nad Labem Region, Czech Republic