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Montbrayite
A valid IMA mineral species - grandfathered
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About Montbrayite
Formula:
(Au,Ag,Sb,Bi,Pb)23(Te,Sb,Bi,Pb)38
Originally assumed to be (Au,Sb)2Te3.
Lustre:
Metallic
Hardness:
2½
Specific Gravity:
9.94
Crystal System:
Triclinic
Name:
After the discovery site, the Robb-Montbray mine and Montbray Township.
Compare the chemically similar 'UM1984-41-Te:AuSb'.
The former formula, (Au,Sb)2Te3, was changed due to the IMA 17-F redefinition proposal.
The former formula, (Au,Sb)2Te3, was changed due to the IMA 17-F redefinition proposal.
Unique Identifiers
Mindat ID:
2761
Long-form identifier:
mindat:1:1:2761:4
IMA Classification of Montbrayite
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Redefined by the IMA
First published:
1947
Approval history:
IMA 17-F
Classification of Montbrayite
2.DB.20
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
D : Metal Sulfides, M: S = 3 :4 and 2:3
B : M:S = 2:3
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
D : Metal Sulfides, M: S = 3 :4 and 2:3
B : M:S = 2:3
2.11.8.1
2 : SULFIDES
11 : AmBnXp, with (m+n):p = 2:3
2 : SULFIDES
11 : AmBnXp, with (m+n):p = 2:3
3.3.14
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
3 : Sulphides etc. of Au
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
3 : Sulphides etc. of Au
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mnb | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mnb | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Montbrayite
Metallic
Transparency:
Opaque
Comment:
Very light yellow
Hardness:
2½ on Mohs scale
Tenacity:
Very brittle
Cleavage:
Very Good
(110), (011), 111
(110), (011), 111
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
9.94 g/cm3 (Measured)
Chemistry of Montbrayite
Mindat Formula:
(Au,Ag,Sb,Bi,Pb)23(Te,Sb,Bi,Pb)38
Originally assumed to be (Au,Sb)2Te3.
Originally assumed to be (Au,Sb)2Te3.
Element Weights:
| Element | % weight |
|---|---|
| Te | 51.698 % |
Calculated from ideal end-member formula.
Common Impurities:
Ag,Pb,Bi,S
Chemical Analysis
wt%
| 1 | |
|---|---|
| Au | 47.7 % |
| Ag | 0.60 % |
| Sb | 0.30 % |
| Pb | 1.3 % |
| Bi | 2.9 % |
| Te | 47.0 % |
| Total: | 99.8 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Robb-Montbray Mine, Rouyn-Noranda TE, Abitibi-Témiscamingue, Québec, Canada | EMPA of 100 micron grain associated with calaverite. |
Crystallography of Montbrayite
Crystal System:
Triclinic
Class (H-M):
1 - Pedial
Space Group:
P1
Cell Parameters:
a = 12.11 Å, b = 13.44 Å, c = 10.80 Å
α = 104.38°, β = 97.50°, γ = 107.93°
α = 104.38°, β = 97.50°, γ = 107.93°
Ratio:
a:b:c = 0.901 : 1 : 0.804
Unit Cell V:
1,578.64 ų (Calculated from Unit Cell)
Z:
12
Morphology:
Crystals very rare
Twinning:
Observed
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0014682 | Montbrayite | Bachechi F (1971) Crystal structure of montbrayite Nature Physical Science 231 67-68 | 1971 | Robb-Montbray, Quebec | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.2 Å | (10) |
| 9.302 Å | (10) |
| 7.363 Å | (20) |
| 4.425 Å | (40) |
| 4.009 Å | (5) |
| 3.812 Å | (10) |
| 3.644 Å | (5) |
| 3.535 Å | (10) |
| 3.442 Å | (5) |
| 3.196 Å | (10) |
| 3.062 Å | (5) |
| 2.983 Å | (80) |
| 2.922 Å | (60) |
| 2.588 Å | (5) |
| 2.469 Å | (5) |
| 2.456 Å | (10) |
| 2.352 Å | (10) |
| 2.320 Å | (10) |
| 2.274 Å | (10) |
| 2.119 Å | (40) |
| 2.087 Å | (100) |
Comments:
ICDD 25-364 Synthetic
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Montbrayite
Associated Minerals at Type Locality:
Other Language Names for Montbrayite
Common Associates
Associations Based on Photo Data:
| 2 photos of Montbrayite associated with Krennerite | Au3AgTe8 |
| 2 photos of Montbrayite associated with Frohbergite | FeTe2 |
| 1 photo of Montbrayite associated with Altaite | PbTe |
| 1 photo of Montbrayite associated with Petzite | Ag3AuTe2 |
| 1 photo of Montbrayite associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 2.DB. | Stangersite | SnGeS3 |
| 2.DB.05 | Antimonselite | Sb2Se3 |
| 2.DB.05 | Metastibnite | Sb2S3 |
| 2.DB.05 | Pääkkönenite | Sb2AsS2 |
| 2.DB.05 | Bismuthinite | Bi2S3 |
| 2.DB.05 | Stibnite | Sb2S3 |
| 2.DB.05 | Guanajuatite | Bi2Se3 |
| 2.DB.10 | Suredaite | PbSnS3 |
| 2.DB.10 | Ottemannite | Sn2S3 |
| 2.DB.15 | Kashinite | Ir2S3 |
| 2.DB.15 | Bowieite | Rh2S3 |
| 2.DB.25 | Edgarite | FeNb3S6 |
| 2.DB.30 | Tarkianite | (Cu,Fe)(Re,Mo)4S8 |
| 2.DB.35 | Cameronite | Cu5-x(Cu,Ag)3+xTe10 (x = 0.43) |
| 2.DB.40 | 'Schreibersite (of Shephard)' | Cr2S3 |
Fluorescence of Montbrayite
Not fluorescent in UV
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 Montbrayite
mindat.org URL:
https://www.mindat.org/min-2761.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Montbrayite
Reference List:
Peacock, M. A., Thompson, R. M. (1946) Montbrayite, a new gold telluride. American Mineralogist, 31 (11-12) 515-526
Thompson, R. M. (1949) The telluride minerals and their occurrence in Canada. American Mineralogist, 34 (5-6) 341-382
BACHECHI, F. (1971) Crystal Structure of Montbrayite. Nature Physical Science, 231. 67-68 doi:10.1038/physci231067a0
Bachechi, F. (1972) Synthesis and stability of montbrayite, Au2Te3. American Mineralogist, 57 (1-2) 146-154
Bindi, Luca, Paar, Werner H., Lepore, Giovanni O. (2018) Montbrayite, (Au,Ag,Sb,Pb,Bi)23(Te,Sb,Pb,Bi)38, From the Robb-Montbray Mine, Montbray, Québec: Crystal Structure and Revision of the Chemical Formula. The Canadian Mineralogist, 56 (2) 129-142 doi:10.3749/canmin.1700095
Vikent’eva, Olga V.; Shilovskikh, Vladimir V.; Shcherbakov, Vasily D.; Moroz, Tatyana N.; Vikentyev, Ilya V.; Bortnikov, Nikolay S. (2023) Montbrayite from the Svetlinsk Gold–Telluride Deposit (South Urals, Russia): Composition Variability and Decomposition. Minerals, 13 (9). 1225 doi:10.3390/min13091225
Localities for Montbrayite
Showing 29 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.
Australia | |
| Shackleton et al. (2003) |
| Mueller et al. (2020) | |
Bulgaria | |
| Bonev +3 other references |
Canada (TL) | |
| 395-404. +5 other references |
| Kasprowicz (2023) |
China | |
| Changjin Cai (1993) |
| Changfu Chen et al. (1999) |
Fiji | |
| Scherbarth et al. (2006) |
Finland | |
| Nebocat et al. (2011) +1 other reference |
| Hytönen (1999) |
| Geological Survey of Finland 2008. Pampalo (Ward) | |
| Kinnunen |
Kazakhstan | |
| Spiridonov (2014) +1 other reference |
| Глоба В.А. Месторождение Манка - новый геолого-промышленный тип месторождений золота. // Изв. НАН РК et al. (403) |
Mexico | |
|
Robb-Montbray Mine, Rouyn-Noranda TE, Abitibi-Témiscamingue, Québec, Canada