Montanite
A valid IMA mineral species
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About Montanite
Flag of Montana, USA
Formula:
Bi2(TeO6) · nH2O
0 ≤ n ≤ 2/3.
Originally thought to be Bi2(TeO6) · 2H2O.
Originally thought to be Bi2(TeO6) · 2H2O.
Colour:
Yellowish, greenish to white
Lustre:
Waxy, Dull
Specific Gravity:
3.7
Crystal System:
Hexagonal
Name:
From the locality where it was found in the state of Montana, USA.
An alteration product of Tetradymite.
"Type localities are Highland, Montana, USA (sample BM 85116), and David Beck’s Mine, North Carolina, USA (sample BM 1985, Nev336)."
Crystal structure details:
* 50% of the Bi and 100% of the Te atoms have trigonal-prismatic coordination, by six oxygen atoms;
* the remainder of the Bi atoms has the coordination number of 7
* water is present within a network of intra-framework cavities
"Type localities are Highland, Montana, USA (sample BM 85116), and David Beck’s Mine, North Carolina, USA (sample BM 1985, Nev336)."
Crystal structure details:
* 50% of the Bi and 100% of the Te atoms have trigonal-prismatic coordination, by six oxygen atoms;
* the remainder of the Bi atoms has the coordination number of 7
* water is present within a network of intra-framework cavities
Unique Identifiers
Mindat ID:
2760
Long-form identifier:
mindat:1:1:2760:7
GUID
(UUID V4):
(UUID V4):
8e7e9796-3e80-466b-a14e-fbcb9aa1f9fd
IMA Classification of Montanite
Approved
IMA status notes:
Redefined by the IMA
IMA Formula:
Bi3+2Te6+O6 · nH2O (0 ≤ n ≤ 2/3)
First published:
1868
Approval history:
Redefined (with different water content) in 2022 (IMA 22-A: "redefinition of montanite").
Type description reference:
Classification of Montanite
7.CD.60
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
D : With only large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
D : With only large cations
Dana 7th ed.:
33.2.2.1
33.2.2.1
33 : SELENATES AND TELLURATES
2 : (AB)m(XO6)·xH2O, where x can equal zero
33 : SELENATES AND TELLURATES
2 : (AB)m(XO6)·xH2O, where x can equal zero
28.4.14
28 : Selenites, Selenates, Tellurites, and Tellurates
4 : Tellurates
28 : Selenites, Selenates, Tellurites, and Tellurates
4 : Tellurates
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 |
|---|---|---|
| Mta | 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 Montanite
Waxy, Dull
Transparency:
Opaque
Colour:
Yellowish, greenish to white
Comment:
Soft
Density:
3.7(1) g/cm3 (Measured)
Optical Data of Montanite
Type:
Biaxial (-)
RI values:
nα = 2.090(3) nβ = 2.090(3)
Max Birefringence:
δ = 2.090
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Very High
Dispersion:
r < v extreme
Comments:
2V = small
Chemistry of Montanite
Mindat Formula:
Bi2(TeO6) · nH2O
0 ≤ n ≤ 2/3.
Originally thought to be Bi2(TeO6) · 2H2O.
0 ≤ n ≤ 2/3.
Originally thought to be Bi2(TeO6) · 2H2O.
Elements listed:
Crystallography of Montanite
Crystal System:
Hexagonal
Class (H-M):
6 - Trigonal Dipyramidal
Space Group:
P6
Cell Parameters:
a = 9.1195(14) Å, c = 5.5694(8) Å
Ratio:
a:c = 1 : 0.611
Unit Cell V:
401.13 ų
Z:
3
Morphology:
Earthy to compact.
Comment:
supercell was only observed in the synthetic analogue
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.49 Å | (100) |
| 1.896 Å | (100) |
| 2.576 Å | (75) |
| 1.503 Å | (50) |
| 3.187 Å | (40) |
| 2.027 Å | (40) |
| 1.255 Å | (35) |
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] |
Type Occurrence of Montanite
Co-Type Localities:
General Appearance of Type Material:
Fibrous, earthy to compact, massive.
Place of Conservation of Type Material:
Two neotypes, both at the Natural History Museum, London, UK.
Associated Minerals at Type Locality:
Reference:
Genth F A (1868) Contributions to mineralogy - No. VII. American Journal of Science and Arts 95, 305-321
Other Language Names for Montanite
Common Associates
Associated Minerals Based on Photo Data:
| 8 photos of Montanite associated with Quartz | SiO2 |
| 6 photos of Montanite associated with Bodieite | Bi2(TeO3)2(SO4) |
| 6 photos of Montanite associated with Goldfieldite | (Cu4◻2)(Cu4Cu+2)Te4S12S |
| 4 photos of Montanite associated with Tetradymite | Bi2Te2S |
| 3 photos of Montanite associated with Gold | Au |
| 2 photos of Montanite associated with Calaverite | AuTe2 |
| 1 photo of Montanite associated with Yecoraite | Fe3+3Bi5(Te6+O4)2(Te4+O3)O9 · 9H2O |
| 1 photo of Montanite associated with Anatase | TiO2 |
| 1 photo of Montanite associated with Rock Crystal | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 7.CD. | Argesite | (NH4)7Bi3Cl16 |
| 7.CD. | Campostriniite | (Bi3+,Na)3(NH4,K)2Na2(SO4)6 · H2O |
| 7.CD.05 | Matteuccite | NaHSO4 · H2O |
| 7.CD.10 | Mirabilite | Na2SO4 · 10H2O |
| 7.CD.15 | Lecontite | (NH4,K)NaSO4 · 2H2O |
| 7.CD.20 | Hydroglauberite | Na10Ca3(SO4)8 · 6H2O |
| 7.CD.25 | Eugsterite | Na4Ca(SO4)3 · 2H2O |
| 7.CD.30 | Görgeyite | K2Ca5(SO4)6 · H2O |
| 7.CD.35 | Koktaite | (NH4)2Ca(SO4)2 · H2O |
| 7.CD.35 | Syngenite | K2Ca(SO4)2 · H2O |
| 7.CD.35 | Antofagastaite | Na2Ca(SO4)2 · 1.5H2O |
| 7.CD.40 | Gypsum | CaSO4 · 2H2O |
| 7.CD.45 | Bassanite | Ca(SO4) · 0.5H2O |
| 7.CD.45 | Chinleite-(Y) | NaY(SO4)2 · H2O |
| 7.CD.45 | Chinleite-(Nd) | NaNd(SO4)2 · H2O |
| 7.CD.50 | Zircosulfate | (Zr,Ti)(SO4)2 · 4H2O |
| 7.CD.55 | Schieffelinite | Pb10Te6+6O20(OH)14(SO4)(H2O)5 |
| 7.CD.65 | Omongwaite | Na2Ca5(SO4)6 · 3H2O |
Other Information
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 Montanite
mindat.org URL:
https://www.mindat.org/min-2760.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Montanite
Reference List:
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin Vol. 679. US Geological Survey doi:10.3133/b679 p.112
Localities for Montanite
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.
Australia | |
| Palache et al. (1951) |
| Gilligan (1975) |
| Palache et al. (1951) | |
| Simpson (1948) |
Austria | |
| Feitzinger (1992) |
| Niedermayr et al. (1995) |
| Paar et al. (2019) | |
| Niedermayr et al. (1995) |
| Auer (2019) |
Belgium | |
| BLONDIEAU M. et al. (2017) |
China | |
| Yingchen Ren et al. (1986) |
Hungary | |
| Szakáll-Gatter-Szendrei:Hungarian ... |
Poland | |
| Gołębiowska et al. (2011) |
Russia | |
| Sidorov et al. (2007, November) |
Slovakia | |
| Ferenc Š et al. (Kokava nad Rimavicou) |
| Bakoš F. et al. (Slovenské Rudohorie, veporikum) |
| Sejkora J. et al. (Vtáčnik, Slovenská republika) |
| Sejkora J. et al. (2004) | |
Tajikistan | |
| Badalov et al. (1975) |
| Novgorodova et al. (1991) +1 other reference |
Tanzania | |
| Mnali (2001) |
USA | |
| Grant et al. (2005) |
| Eckel et al. (1997) |
| American Journal of Science (1868) +2 other references |
| Gobla (2012) | |
| Castor et al. (2004) |
| Castor et al. (2004) |
| Palache et al. (1951) +1 other reference |
| Crawford (1937) +1 other reference |
| Rocks & Min.:60:86. |
| Genth F A (1868) +1 other reference |
| Genth | |
| Genth | |
| Mineralogical Magazine +1 other reference |
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Pod Angleta, Župkov occurrences, Župkov, Žarnovica District, Banská Bystrica Region, Slovakia