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n.1.(Crystallog.) A solid in the isometric system, bounded by twenty-four equal triangular faces, four corresponding to each face of the cube.
References in periodicals archive ?
Three crystal forms in several combinations have been identified: the cube {100}; the octahedron {111}; and the tetrahexahedron {015}.
A few topazolite crystals recovered in December 2009 are modified by the trisoctahedron {332} and tetrahexahedron {210}.
A close examination of the rounded edges reveals minute facets of the dodecahedron, tetrahexahedron and trapezohedron.
In the late 1980s the mine yielded large specimens with transparent, gray-violet to purple cubic crystals, commonly penetration-twinned and displaying tetrahexahedron faces; in 1990 a cavity on the 340 level gave up abundant specimens showing purple cubic crystals on matrix, some with good galena crystals.
Forms present are the cube (a), octahedron (o), dodecahedron (d), tetrahexahedron (e) {012}, trapezohedron (m) {113}, trisoctahedron (q) {133}, and hexoctahedron (t) {124}.
The Orapa diamond mine in Botswana has recently yielded a remarkable specimen best described as an apparent hoppered tetrahexahedron of yellow diamond.
There is also--and this is part of what I meant earlier by "playful"--a piece by Erich Offermann and Pete Richards called "Fluorite Balls From Hell," in which a computer-enabled, almost insanely detailed crystallographic analysis is offered of tiny fluorite crystals from Germany which typically look like spheres because they combine the hexoctahedron (48 faces), tetrahexahedron (24 faces), cube, dodecahedron, trapezohedron and (for all I could tell, on a quick read) even more isometric forms, all in more or less equal development.
5 cm, showing the dodecahedron, tetrahexahedron, and minor rough (and very unusual) cube faces occur in the Mohmand FATA about 30-50 km (20-30 miles) from Zagi, but labels on some marketed specimens have attributed them to Zagi Mountain, apparently to enhance their value.
Modification of the cube edges by the tetrahexahedron form (0121 is well-developed on about 10% of the crystals.