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Great icosahedron

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Great icosahedron
Type Kepler–Poinsot polyhedron
Stellation core icosahedron
Elements F = 20, E = 30
V = 12 (χ = 2)
Faces by sides 20{3}
Schläfli symbol {3,52}
Face configuration V(53)/2
Wythoff symbol 52 | 2 3
Coxeter diagram
Symmetry group Ih, H3, [5,3], (*532)
References U53, C69, W41
Properties Regular nonconvex deltahedron

(35)/2
(Vertex figure)

Great stellated dodecahedron
(dual polyhedron)

In geometry, the great icosahedron is a Kepler-Poinsot solid. It is one of four nonconvex regular polyhedra. It is composed of 20 triangular faces, with five triangles meeting at each vertex in a pentagrammic sequence.

The 12 vertices match the locations for an icosahedron. The 30 edges are shared by the small stellated dodecahedron.


A transparent model of the great icosahedron (See also Animation)

As a stellation

It is also a stellation of the icosahedron, counted by Wenninger as model [W41] and the 16th of 17 stellations of the icosahedron and 7th of 59 stellations by Coxeter.

The stellation facets for construction are:

References

  • Wenninger, Magnus (1974). Polyhedron Models. Cambridge University Press. ISBN 0-521-09859-9.
  • Coxeter, H. S. M. (1938). The Fifty-Nine Icosahedra. Springer-Verlag, New York, Berlin, Heidelberg. ISBN 0-387-90770-X.