Proxidecagonite
A valid IMA mineral species
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Formula:
Al34Ni9Fe2
Colour:
Grey to black
Lustre:
Metallic
Crystal System:
Orthorhombic
Name:
The name is derived from “periodic approximant of decagonite”; from the truncated Latin word proxǐmus followed by the name of the quasicrystalline mineral decagonite.
New structure type.
Unique Identifiers
Mindat ID:
53058
Long-form identifier:
mindat:1:1:53058:9
IMA Classification of Proxidecagonite
Approved
Approval year:
2018
First published:
2018
Approval history:
IMA 2018-038
Classification of Proxidecagonite
1.AA.50
1 : ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)
A : Metals and Intermetallic Alloys
A : Copper-cupalite family
1 : ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)
A : Metals and Intermetallic Alloys
A : Copper-cupalite family
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 |
|---|---|---|
| Pdec | 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 Proxidecagonite
Optical Data of Proxidecagonite
Anisotropism:
Without characteristic rotation-tints.
Bireflectance:
Weak to moderate
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 471nm | 28.8% | 31.2% |
| 548nm | 29.4% | 32.0% |
| 586nm | 30.6% | 32.8% |
| 652nm | 31.5% | 33.7% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 33.7%.
R1 shown in black, R2 shown in red
Internal Reflections:
Absent
Pleochroism:
Non-pleochroic
Chemistry of Proxidecagonite
Mindat Formula:
Al34Ni9Fe2
Element Weights:
Elements listed:
Crystallography of Proxidecagonite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Setting:
Pnma
Cell Parameters:
a = 29.013(3) Å, b = 8.156(1) Å, c = 12.401(2) Å
Ratio:
a:b:c = 3.557 : 1 : 1.52
Unit Cell V:
2934.4 ų
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.96 Å | (50) |
| 3.80 Å | (40) |
| 3.403 Å | (40) |
| 2.069 Å | (50) |
| 2.045 Å | (100) |
| 2.036 Å | (30) |
| 2.033 Å | (50) |
| 2.024 Å | (70) |
Locality:
Reference:
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
Type Occurrence of Proxidecagonite
General Appearance of Type Material:
20 µm anhedral grain.
Place of Conservation of Type Material:
Type material is deposited in the mineralogical collections of the Museo di Storia Naturale – Sezione di Mineralogia e Litologia, Università di Firenze, Via La Pira 4, I-50121 Firenze, Italy, catalogue number 3291/I.
Geological Setting of Type Material:
Meteoritic fragments of the Khatyrka meteorite.
Associated Minerals at Type Locality:
Synonyms of Proxidecagonite
Other Language Names for Proxidecagonite
Dutch:Proxidecagoniet
German:Proxidecagonit
Related Minerals - Strunz-mindat Grouping
| 1.AA. | Jonlarsenite | Al4Cu9 |
| 1.AA. | Pratesiite | AgCuTe2 |
| 1.AA.05 | Native Lead | Pb |
| 1.AA.05a | Auricupride Subgroup | |
| 1.AA.05 | Native Nickel | Ni |
| 1.AA.05 | Native Silver | Ag |
| 1.AA.05 | 'UM2004-08-E:AuCuPd' | Cu2PdAu |
| 1.AA.05 | 'UM1991-06-E:AuCu' | Au3Cu |
| 1.AA.05 | Native Aluminium | Al |
| 1.AA.05 | Steinhardtite | Al0.38Ni0.32Fe0.30 |
| 1.AA.05 | Native Gold | Au |
| 1.AA.05 | Native Copper | Cu |
| 1.AA.05 | Copper Group | |
| 1.AA.10a | Cuproauride | Cu3Au |
| 1.AA.10b | Tetra-auricupride | AuCu |
| 1.AA.10a | Auricupride | Cu3Au |
| 1.AA.10 | Nickel Group | |
| 1.AA.15 | Anyuiite | AuPb2 |
| 1.AA.15 | Novodneprite | AuPb3 |
| 1.AA.15 | 'UM1985-02-E:AlZn' | (Zn,Cu)Al2 |
| 1.AA.15 | Khatyrkite | (Cu,Zn)Al2 |
| 1.AA.20 | Cupalite | (Cu,Zn)Al |
| 1.AA.25 | Hunchunite | Au2Pb |
| 1.AA.30 | Stolperite | AlCu |
| 1.AA.35 | Hollisterite | Al3Fe |
| 1.AA.40 | Icosahedrite | Al63Cu24Fe13 |
| 1.AA.45 | Kryachkoite | (Al,Cu)6(Fe,Cu) |
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 Proxidecagonite
mindat.org URL:
https://www.mindat.org/min-53058.html
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External Links:
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References for Proxidecagonite
Reference List:
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2018) CNMNC Newsletter No. 44, New minerals and nomenclature modifications approved in 2018. Mineralogical Magazine, 82 (4) 1015-1021 doi:10.1180/mgm.2018.148p.1020
Bindi, Luca; Pham, Joyce; Steinhardt, Paul J. (2018) Previously unknown quasicrystal periodic approximant found in space. Scientific Reports, 8. 16271 doi:10.1038/s41598-018-34375-x
Localities for Proxidecagonite
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) | |
| Hålenius et al. (2018) +1 other reference |
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