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Arsmirandite
A valid IMA mineral species
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About Arsmirandite
Formula:
Na18Cu12Fe3+O8(AsO4)8Cl5
Colour:
Dark greyish green to olive-greenish black
Lustre:
Vitreous
Specific Gravity:
3.715 (Calculated)
Crystal System:
Monoclinic
Name:
For Latin mirandus, marvelous, to reflect the unusual crystal structure that, moreover, is As-rich.
New structure type. Co-described with lehmannite from which it is visually indistinguishable.
The two have similar, unique structural features:
- Fe3+ (or Ti4+, in lehmannite) in cubic coordination;
- packing of unusual, nanoscale (~1.5 nm across) clusters, of the {[MCu12O8](AsO4)8} composition; M = Fe3+ in arsmirandite
Na and halogen atoms are between the nanoclusters.
Associates also include various arsenates and sulfates.
The two have similar, unique structural features:
- Fe3+ (or Ti4+, in lehmannite) in cubic coordination;
- packing of unusual, nanoscale (~1.5 nm across) clusters, of the {[MCu12O8](AsO4)8} composition; M = Fe3+ in arsmirandite
Na and halogen atoms are between the nanoclusters.
Associates also include various arsenates and sulfates.
Unique Identifiers
Mindat ID:
46530
Long-form identifier:
mindat:1:1:46530:0
IMA Classification of Arsmirandite
Approved
IMA Formula:
Na18Cu2+12Fe3+O8(As5+O4)8Cl5
Approval year:
2014
First published:
2020
Classification of Arsmirandite
8.BK.35
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
K : With medium-sized and large cations, (OH, etc.):RO4 = 2:1, 2.5:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
K : With medium-sized and large cations, (OH, etc.):RO4 = 2:1, 2.5:1
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 |
|---|---|---|
| Asm | 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 Arsmirandite
Vitreous
Transparency:
Translucent, Opaque
Comment:
"Strong vitreous"
Colour:
Dark greyish green to olive-greenish black
Comment:
Translucent only in thin sections.
Streak:
Greyish green with an olive hue.
Hardness Data:
Could not be measured
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
None observed.
Fracture:
Irregular/Uneven
Density:
3.715 g/cm3 (Calculated)
Optical Data of Arsmirandite
Anisotropism:
Very weak.
Bireflectance:
Very weak.
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 400nm | 7.2% | 7.5% |
| 420nm | 7.4% | 7.7% |
| 440nm | 7.4% | 7.7% |
| 460nm | 7.3% | 7.6% |
| 470nm | 7.3% | 7.6% |
| 480nm | 7.2% | 7.5% |
| 500nm | 7.1% | 7.4% |
| 520nm | 7.0% | 7.3% |
| 540nm | 6.9% | 7.2% |
| 546nm | 6.9% | 7.2% |
| 560nm | 6.9% | 7.1% |
| 580nm | 6.8% | 7.1% |
| 589nm | 6.8% | 7.1% |
| 600nm | 6.8% | 7.0% |
| 620nm | 6.7% | 7.0% |
| 640nm | 6.7% | 7.0% |
| 650nm | 6.7% | 7.0% |
| 660nm | 6.7% | 6.9% |
| 680nm | 6.7% | 6.9% |
| 700nm | 6.7% | 6.9% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 7.7%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Dark gray
Pleochroism:
Not Visible
Chemistry of Arsmirandite
Mindat Formula:
Na18Cu12Fe3+O8(AsO4)8Cl5
Element Weights:
Crystallography of Arsmirandite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 10.742(2) Å, b = 21.019(3) Å, c = 11.787(2) Å
β = 117.06(3)°
β = 117.06(3)°
Ratio:
a:b:c = 0.511 : 1 : 0.561
Unit Cell V:
2370 ų
Morphology:
Individual crystals are equant, thick tabular or short prismatic, with pyramid-like terminations.
Twinning:
Cyclic interpenetration twins, similar to phillipsite.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.58 Å | (79) |
| 8.74 Å | (100) |
| 5.381 Å | (46) |
| 5.288 Å | (80) |
| 3.770 Å | (33) |
| 2.693 Å | (28) |
| 2.643 Å | (30) |
| 2.574 Å | (74) |
Comments:
Arsenatnaya fumarole, Kamchatka Krai, Russia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 45b : [Other oxidized fumarolic minerals] |
Type Occurrence of Arsmirandite
General Appearance of Type Material:
Equant crystals, up to 20 × 20 × 30 sq. μm, usually intergrown to form thin crusts, up to 2 × 3 cm in area.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4613/1.
Geological Setting of Type Material:
Volcanic fumarole.
Associated Minerals at Type Locality:
Synonyms of Arsmirandite
Other Language Names for Arsmirandite
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 8.BK.05 | Brazilianite | NaAl3(PO4)2(OH)4 |
| 8.BK.10 | Neustädtelite | Bi2Fe3+(Fe3+,Co)(AsO4)2(O,OH)4 |
| 8.BK.10 | Cobaltneustädtelite | Bi2Fe3+(Co,Fe3+)(AsO4)2(O,OH)4 |
| 8.BK.10 | Medenbachite | Bi2Fe3+Cu2+(AsO4)2O(OH)3 |
| 8.BK.15 | Curetonite | Ba(Al,Ti)(PO4)(OH,O)F |
| 8.BK.20 | Heyite | Pb5Fe2+2(VO4)2O4 |
| 8.BK.25 | Jamesite | Pb2Zn(Fe2+,Zn)2Fe3+4(AsO4)4(OH)10 |
| 8.BK.25 | Lulzacite | Sr2Fe2+(Fe2+,Mg)2Al4(PO4)4(OH)10 |
| 8.BK.25 | Désorite | Pb2(Fe3+6Zn)O2(PO4)4(OH)8 |
| 8.BK.30 | Nishanbaevite | KAl2O(AsO4)(SO4) |
| 8.BK.35 | Zircarsite | Na18Cu12ZrO8(AsO4)8Cl6 |
| 8.BK.35 | Lebedevite | K4Na14Cu14O8(AsO4)8Cl6 |
| 8.BK.35 | Lehmannite | Na18Cu12TiO8(AsO4)8FCl5 |
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 Arsmirandite
mindat.org URL:
https://www.mindat.org/min-46530.html
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References for Arsmirandite
Localities for Arsmirandite
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.
Russia (TL) | |
| Shchipalkina et al. (2019) +2 other references |
Quick NavTopAbout ArsmiranditeUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik Volcanic field, Milkovsky District, Kamchatka Krai, Russia