Icosahedrite (original) (raw)

A valid IMA mineral species

About IcosahedriteHide

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Crystal System:

Icosahedral

Name:

Named for the icosahedral symmetry of its internal atomic arrangement, as observed in its diffraction pattern.

The first quasicrystal (http://en.wikipedia.org/wiki/Quasicrystal) described as a mineral species.

Compare decagonite, the second natural quasicrystal approved.

Chemically similar to 'Unnamed (Al-Cu-Fe Alloy)' and 'Unnamed (Al-Cu-Fe Alloy II)'.

The vast majority of minerals are crystalline materials, with structures in which a particular arrangement of atoms repeats regularly by translation, like a 3-D wallpaper pattern. Only certain types of rotation axes in the crystal symmetry are compatible with this: 2-fold, 3-fold, 4-fold and 6-fold rotations, and the combination of four 3-fold axes with additional 2- and/or 4-fold axes that gives rise to "cubic" symmetry.

Quasicrystals are a recently discovered type of solid material that use quite different organising principles for arranging their atoms. They do not have an atomic arrangement which repeats regularly by translation, but they do have rotational symmetry about axes which can be of "crystallographically forbidden" orders such as 5-fold, 8-fold, 10-fold and 12-fold, as well as the combination of six intersecting 5-fold axes that is characteristic of the Platonic dodecahedron and icosahedron. Despite the absence of a straightforward, regular repeat unit, they retain a high degree of organisation. Quasicrystalline structures can be made by using more than one type of building block, which fit together via stringent rules so that there are no gaps, no overlaps, but also no repetition. There is still enough regularity in the structure that sharp periodicities occur in the diffraction pattern, albeit with a fractal distribution rather than uniform spacing of frequencies.

Quasicrystal diffraction patterns were first obtained from synthetic aluminium-manganese alloys by Dan Shechtman in 1982, but early observations were regarded with considerable scepticism, even by such eminent crystallographers as Linus Pauling. However, more and more examples were discovered independently by
several research teams, and thermodynamic stability in a quasicrystal alloy was first shown in 1987. Hundreds of synthetic quasicrystal materials are now known, along with chemically similar "approximant" compounds in which regular repeating mistakes convert the quasicrystal atomic arrangement into a normal crystal.

Although quasicrystals can have a well-defined point group ("crystal class") symmetry, they are aperiodic, so other conventional crystallographic concepts such as "lattice type", "space group","unit cell parameters" and "unit cell content" do not apply to the structure as normally considered in three dimensions. However,
it is mathematically possible to generate quasicrystalline structures by taking 3-D slices that are precisely but irrationally oriented through higher-dimensional structures that are periodic: the icosahedral-symmetry quasicrystalline structure of icoashedrite can then be described as a carefully chosen slice through a 6-dimensional hypercubic (hyper)crystal!

In 2011, Dan Shechtman received the Nobel Prize in Chemistry for his discovery of the first quasicrystal. The year previously, Luca Bindi's icosahedrite, the first naturally-occuring quasicrystal, was approved as a new mineral by the Commission on New Minerals and Mineral Classification (IMA 2010-042).

In 2012, Bindi's group published evidence that natural icosahedrite is extraterrestrial in origin. It occurs with other Cu-Al-Fe alloys and a suite of silicates and oxides such as diopside, forsterite, spinel and the extremely high-pressure SiO2 polymorph stishovite (which contains icosahedrite as inclusions!). The assemblage and oxygen isotopic composition are consistent with formation not on Earth, but in a refractory calcium-aluminium-rich inclusion in a CV3 chondritic meteorite.

See also Bindi et al. (2022) paper on another - dodecagonal - quasicrystal, Unnamed (Mn-Si-Cr-Al-Ni Quasicrystal), forrmed via interaction of a lightning and an eolian dune.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:40647:7

ee951607-f399-429d-9917-9a14b01346e7

IMA Classification of IcosahedriteHide

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Classification of IcosahedriteHide

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1.AA.40

1 : ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)
A : Metals and Intermetallic Alloys
A : Copper-cupalite family

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 IcosahedriteHide

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Fracture:

Irregular/Uneven

Comment:

The density could not be determined.

Optical Data of IcosahedriteHide

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Reflectivity:

Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 62.3%.

Comments:

Reflectance percentages (Rmin = Rmax) for the four standard COM wavelengths are 62.3 (471.1 nm), 60.6 (548.3 nm), 58.1 (586.6 nm), and 56.0 (652.3 nm), respectively.

Chemistry of IcosahedriteHide

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Mindat Formula:

Al63Cu24Fe13

Common Impurities:

Al62.2Cu25.7Fe10.7Si0.4Ni0.1Cr0.1

Crystallography of IcosahedriteHide

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Crystal System:

Icosahedral

Class (H-M):

53_m_ - point symmetry group

Morphology:

Anhedral to subhedral grains <0.1mm in the type specimen.

Comment:

The structure is not reducible to a single three-dimensional unit cell, so neither cell parameters nor Z can be given. The X-ray powder pattern was indexed on the basis of six integer indices, as conventionally used with quasicrystals, where the lattice parameter (in six-dimensional notation) is measured to be a6D = 12.64 Å, with probable space group Fm-3-5.

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Geological Setting:

hollisterite- and stolperite-bearing association

Type Occurrence of IcosahedriteHide

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General Appearance of Type Material:

Dark gray-black anhedral to subhedral grains up to 100 μm across.

Place of Conservation of Type Material:

Natural History Museum, University of Florence, Italy (46407/G).

Geological Setting of Type Material:

Associated Minerals at Type Locality:

Synonyms of IcosahedriteHide

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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 IcosahedriteHide

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References for IcosahedriteHide

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Reference List:

Bindi, L., Steinhardt, P. J., Yao, N., Lu, P. J. (2011) Icosahedrite, Al63Cu24Fe13, the first natural quasicrystal. American Mineralogist, 96 (5) 928-931 doi:10.2138/am.2011.3758

Bindi, L., Eiler, J. M., Guan, Y., Hollister, L. S., MacPherson, G., Steinhardt, P. J., Yao, N. (2012) Evidence for the extraterrestrial origin of a natural quasicrystal. Proceedings of the National Academy of Sciences, 109 (5) 1396-1401 doi:10.1073/pnas.1111115109

Bindi, Luca, Pasek, Matthew A., Ma, Chi, Hu, Jinping, Cheng, Guangming, Yao, Nan, Asimow, Paul D., Steinhardt, Paul J. (2023) Electrical discharge triggers quasicrystal formation in an eolian dune. Proceedings of the National Academy of Sciences, 120 (1) doi:10.1073/pnas.2215484119

Pereti, Claudio, Bernot, Kevin, Guizouarn, Thierry, Laufek, František, Vymazalová, Anna, Bindi, Luca, Sessoli, Roberta, Fanelli, Duccio (2023) From individual elements to macroscopic materials: in search of new superconductors via machine learning. npj Computational Materials, 9 (1) doi:10.1038/s41524-023-01023-6

Bindi, Luca, Pasek, Matthew A., Ma, Chi, Hu, Jinping, Cheng, Guangming, Yao, Nan, Asimow, Paul D., Steinhardt, Paul J. (2023) Electrical discharge triggers quasicrystal formation in an eolian dune. Proceedings of the National Academy of Sciences, 120 (1) doi:10.1073/pnas.2215484119

Localities for IcosahedriteHide

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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.