pyritohedron


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Related to pyritohedron: Scalenohedron, rhombohedron

pyritohedron

(ˌpaɪrɪtəʊˈhiːdrən)
n, pl -drons or -dra (-drə)
(Minerals) crystallog a twelve-sided polyhedron with pentagonal faces, common in crystals of pyrite
References in periodicals archive ?
The SEM micrographs of the fracture of CEPBS foam showed that after the incorporation of CE, the cell size distribution became uniform, cellular wall became thin, and the cell structure turned oval to pyritohedron.
6 cm in the 1920s (see Wilson, this issue), but this size record was surpassed in the 1990s by sperrylite discovered at Norilsk in well-crystallized cubes modified by octahedron and pyritohedron faces that reach over 4 cm on edge.
The following forms were identified: the rhombic dodecahedron, the pyritohedron, the trapezohedron, several dyakis dodecahedra, and probably the triakis octahedron [= trisoctahedron],
Sharper, smaller crystals as a rule show combinations of the pyritohedron, rhombic dodecahedron, cube and octahedron; cuboctahedrons are especially common whereas simple octahedrons are rare.
Pyrite, a relatively common sulfide in both upper and lower sill cavities, and in dike and limestone cavities, occurs as crystals 1-3 mm in diameter, with the cube as the dominant form, often modified by the {210} pyritohedron and {111} octahedron.
Bateman reports massive pyrite, and one specimen of a distorted pyritohedron, but a search of the Yale collection did not reveal the piece.