Montanite (original) (raw)

A valid IMA mineral species

About MontaniteHide

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0 ≤ n ≤ 2/3.
Originally thought to be Bi2(TeO6) · 2H2O.

Colour:

Yellowish, greenish to white

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

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:2760:7

8e7e9796-3e80-466b-a14e-fbcb9aa1f9fd

IMA Classification of MontaniteHide

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IMA status notes:

Redefined by the IMA

IMA Formula:

Bi3+2Te6+O6 · nH2O (0 ≤ n ≤ 2/3)

Approval history:

Redefined (with different water content) in 2022 (IMA 22-A: "redefinition of montanite").

Type description reference:

Classification of MontaniteHide

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7.CD.60

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
D : With only large cations

33.2.2.1

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

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of MontaniteHide

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Colour:

Yellowish, greenish to white

Density:

3.7(1) g/cm3 (Measured)

Optical Data of MontaniteHide

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RI values:

_n_α = 2.090(3) _n_β = 2.090(3)

δ = 2.090

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Chemistry of MontaniteHide

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Mindat Formula:

Bi2(TeO6) · nH2O

0 ≤ n ≤ 2/3.
Originally thought to be Bi2(TeO6) · 2H2O.

Crystallography of MontaniteHide

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Class (H-M):

6 - Trigonal Dipyramidal

Cell Parameters:

a = 9.1195(14) Å, c = 5.5694(8) Å

Morphology:

Earthy to compact.

Comment:

supercell was only observed in the synthetic analogue

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Type Occurrence of MontaniteHide

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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 MontaniteHide

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Simplified Chinese:碲铋华

Traditional Chinese:碲鉍華

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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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 MontaniteHide

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References for MontaniteHide

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Reference List:

Missen, Owen P., Mills, Stuart J., Rumsey, Michael S., Weil, Matthias, Artner, Werner, Spratt, John, Najorka, Jens (2022) Crystal structure and investigation of Bi2TeO6·nH2O (0 ≤ n ≤ 2/3): natural and synthetic montanite. Physics and Chemistry of Minerals, 49 (7) doi:10.1007/s00269-022-01198-2

Localities for MontaniteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.