octahedra

Diamond crystallizes in the isometric (cubic) system, and regularly forms cubes and octahedra (an octahedra is an 8-sided "diamond-shaped" crystal; see below).

Diamond 2007

It crystallizes in octahedra, having a specific gravity of 3.2, and melts at 597° C. (T. Carnelley).

Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 3 "Banks" to "Bassoon" Various

By sublimation in a current of hydrogen it can be crystallized in the form of regular octahedra; it is slightly harder than tin, but is softer than zinc, and like tin, emits a crackling sound when bent.

Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" Various

By cooling the aqueous solution, hyacinth-red octahedra of a crystalline hydrate of composition

Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" Various

They all crystallize in octahedra and contain twelve molecules of water of crystallization.

An Elementary Study of Chemistry William McPherson

It crystallizes in red octahedra and dyes silk and wool yellow.

Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 1 "Austria, Lower" to "Bacon" Various

If a little more ammonia is added, several varieties of rhombic octahedra appear; if a little nitric acid is added, the rectangular prism appears again.

On the Genesis of Species St. George Mivart

It is worthy of notice that in diatomic elements _four_ funnels open on the faces of tetrahedra; in triatomic, _six_ funnels on the faces of cubes; in tetratomic, _eight_ funnels on the faces of octahedra.

Occult Chemistry Clairvoyant Observations on the Chemical Elements Annie Wood Besant 1890

The rotating square and triangle arrangements by pasting octahedra onto the rotating triangles arrangement, above or below depending on colour, and then repeating this basic unit in planes.

iMechanica - Comments Ajay B Harish 2010

I saw that the cubes could be augmented to form a packing of rhombic dodecahedra, and these could be used in the augmenting the octahedron, and the original "rotating octahedra" transformation can also be modelled with rhombic

iMechanica - Comments Ajay B Harish 2010