Ermakovite
A valid IMA mineral species
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About Ermakovite
Nikolai P. Ermakov
Formula:
(NH4)(As2O3)2Br
Colour:
Yellow
Lustre:
Sub-Adamantine
Hardness:
1 - 1½
Specific Gravity:
3.64
Crystal System:
Hexagonal
Member of:
Name:
Named in honor of Nikolai Porfirievich Ermakov (Николай Порфирьевич Ермаков) (16 November 1913, Kondurchinskaya fortress, Samara province, Russia - 25 September 1993, Moscow , Russia), professor of mineralogy, head of the thermobarogeochemistry lab and founder of the Earth Science Museum at Moscow State University (Russia).
The Br analogue of mauriziodiniite. Known synthetic analogue.
Additional associate: amorphous As2S3.
Details of the sandwich-type structure that has three types of layers
(1) a honeycomb [As2O3] arsenite layer
(2) an NH4+ layer
(3) a Br-layer;
The layer stacking sequence is NH4-As2O3-Br-As2O3-NH4.
Also compare lucabindiite, torrecillasite, and russoite.
Additional associate: amorphous As2S3.
Details of the sandwich-type structure that has three types of layers
(1) a honeycomb [As2O3] arsenite layer
(2) an NH4+ layer
(3) a Br-layer;
The layer stacking sequence is NH4-As2O3-Br-As2O3-NH4.
Also compare lucabindiite, torrecillasite, and russoite.
Unique Identifiers
Mindat ID:
55233
Long-form identifier:
mindat:1:1:55233:2
IMA Classification of Ermakovite
Approved
IMA Formula:
(N3-H4)(As3+2O3)2Br
Approval year:
2020
First published:
2023
Type description reference:
Karpenko, Vladimir Yu., Pautov, Leonid A., Siidra, Oleg I., Mirakov, Mirak A., Zaitsev, Anatoly N., Plechov, Pavel Yu., Makhmadsharif, Saimudasir (2023) Ermakovite (NH4)(As2O3)2Br, a new exhalative arsenite bromide mineral from the Fan-Yagnob coal deposit, Tajikistan. Mineralogical Magazine, 87 (1) 69-78 doi:10.1180/mgm.2022.116
Classification of Ermakovite
3.C0.
3 : HALIDES
C : Complex halides
0 :
3 : HALIDES
C : Complex halides
0 :
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 |
|---|---|---|
| Ekv | 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 Ermakovite
Sub-Adamantine
Transparency:
Transparent
Colour:
Yellow
Comment:
Zoned with a transparent yellowish core and semi-transparent yellow rim.
Streak:
White with a yellowish tint
Hardness:
1 - 1½ on Mohs scale
Hardness:
VHN20=40 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Perfect
(001)
(001)
Fracture:
Irregular/Uneven
Density:
3.64(2) g/cm3 (Measured) 3.747 g/cm3 (Calculated)
Optical Data of Ermakovite
Type:
Uniaxial (-)
RI values:
nω = 1.960(5) nε = 1.716(3)
Max. Birefringence:
δ = 0.244
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Pleochroism:
Non-pleochroic
Chemistry of Ermakovite
Mindat Formula:
(NH4)(As2O3)2Br
Element Weights:
Crystallography of Ermakovite
Crystal System:
Hexagonal
Class (H-M):
6/mmm(6/m2/m2/m) - Dihexagonal Dipyramidal
Space Group:
P6/mmm
Setting:
P6/mmm
Cell Parameters:
a = 5.271(3) Å, c = 9.157(6) Å
Ratio:
a:c = 1 : 1.737
Unit Cell V:
220.33 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Tabular or prismatic, hexagonal crystals, up to 200 μm, with the c (001), m (010), and p (014) forms; commonly as spherolitic and multi-twinned intergrowths.
Twinning:
Multi-twinned intergrowths.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.160 Å | (80) |
| 4.560 Å | (90) |
| 3.228 Å | (100) |
| 2.629 Å | (80) |
| 2.522 Å | (60) |
| 2.276 Å | (40) |
| 1.817 Å | (40) |
| 1.608 Å | (40) |
Reference:
Karpenko, Vladimir Yu., Pautov, Leonid A., Siidra, Oleg I., Mirakov, Mirak A., Zaitsev, Anatoly N., Plechov, Pavel Yu., Makhmadsharif, Saimudasir (2023) Ermakovite (NH4)(As2O3)2Br, a new exhalative arsenite bromide mineral from the Fan-Yagnob coal deposit, Tajikistan. Mineralogical Magazine, 87 (1) 69-78 doi:10.1180/mgm.2022.116
Comments:
From Type Description.
Type Occurrence of Ermakovite
General Appearance of Type Material:
Tabular or prismatic, hexagonal crystals, up to 200 μm, with the c (001), m (010), and p (014) forms; commonly as spherolitic and multi-twinned intergrowths.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskiy Prospekt 18-2, Moscow 119071, Russia, registration number 5525/1.
Empirical Formula of Type Material:
[(NH4)0.92Na0.01]0.93(As3.94Sb0.06)4.00O6.02(Br0.97Cl0.08I0.01)1.06
Geological Setting of Type Material:
Coal-fire-driven exhalative processes within a fumarole.
Associated Minerals at Type Locality:
Reference:
Karpenko, Vladimir Yu., Pautov, Leonid A., Siidra, Oleg I., Mirakov, Mirak A., Zaitsev, Anatoly N., Plechov, Pavel Yu., Makhmadsharif, Saimudasir (2023) Ermakovite (NH4)(As2O3)2Br, a new exhalative arsenite bromide mineral from the Fan-Yagnob coal deposit, Tajikistan. Mineralogical Magazine, 87 (1) 69-78 doi:10.1180/mgm.2022.116
Synonyms of Ermakovite
Other Language Names for Ermakovite
Dutch:Ermakoviet
German:Ermakovit
Relationship of Ermakovite to other Species
Member of:
Other Members of Lucabindiite Group:
| Cuatrocapaite-(K) | K3(NaMg◻)(As2O3)6Cl6 · 16H2O | Trig. 3m(32/m) : R3m |
| Cuatrocapaite-(NH4) | (NH4)3(NaMg◻)(As2O3)6Cl6 · 16H2O | Trig. 3m(32/m) : R3m |
| Gajardoite | KCa0.5As3+4O6Cl2 · 5H2O | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Gajardoite-(NH4) | (NH4)As3+4O6Cl2(Ca0.5◻0.5)(H2O)5 | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Lucabindiite | (K,NH4)As4O6(Cl,Br) | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Mauriziodiniite | (NH4)(As2O3)2I | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Russoite | (NH4)ClAs2O3(H2O)0.5 | Hex. 622 : P622 |
| Torrecillasite | Na(As,Sb)3+4O6Cl | Orth. |
Common Associates
Associations Based on Photo Data:
| 8 photos of Ermakovite associated with Bonazziite | As4S4 |
| 5 photos of Ermakovite associated with Realgar | As4S4 |
Related Minerals - Strunz-mindat Grouping
| 3.C0. | Ammineite | [CuCl2(NH3)2] |
Other Information
Notes:
Insoluble in water, HCl, HNO3 or organic solvents.
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 Ermakovite
mindat.org URL:
https://www.mindat.org/min-55233.html
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Please feel free to link to this page.
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References for Ermakovite
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2020) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 58. European Journal of Mineralogy, 32 (6) 645-651 doi:10.5194/ejm-32-645-2020
Karpenko, Vladimir Yu., Pautov, Leonid A., Siidra, Oleg I., Mirakov, Mirak A., Zaitsev, Anatoly N., Plechov, Pavel Yu., Makhmadsharif, Saimudasir (2023) Ermakovite (NH4)(As2O3)2Br, a new exhalative arsenite bromide mineral from the Fan-Yagnob coal deposit, Tajikistan. Mineralogical Magazine, 87 (1) 69-78 doi:10.1180/mgm.2022.116
Localities for Ermakovite
Showing 1 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.
Tajikistan (TL) | |
| Miyawaki et al. (2020) +1 other reference |
Quick NavTopAbout ErmakoviteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Kukhi-Malik tract, Fan-Jagnob coal deposit, Ayni District, Sughd, Tajikistan