rhombohedron

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Related to rhombohedrons: Scalenohedron

rhombohedron

a six-sided prism whose sides are parallelograms

Rhombohedron

 

a parallelepiped (usually oblique) whose faces are equal rhombuses. For at least two vertices all the adjacent angles must be equal. A parallelepiped is a rhombohedron if and only if it has an axis of three-fold symmetry.

rhombohedron

[¦räm·bō¦hē·drən]
(crystallography)
A trigonal crystal form that is a parallelepiped, the six identical faces being rhombs. Also known as rhomb.
(mathematics)
A prism with six parallelogram faces.
References in periodicals archive ?
The model in Figure 19 illustrates the general features of the calcite rhombohedron of six sides and eight corners, shown here truncated with small planar surfaces and with the c axis vertical, in the plane of the page.
Similarly, the degree of transparency is never as high in Calcite-II as in Calcite-I; however, the larger rhombohedrons of Calcite-II (more than 2 cm) may be transparent.
Not only could Hauy cleave a calcite scalenohedron down until the rhombohedron emerged, but he could also derive the scalenohedral shape by stacking up tiny rhombohedrons in parallel (Hauy, 1801).
they are terminated by three dominant, high-angle rhombohedron faces, and there is a smaller, subordinate rhombohedron, and the prism faces show prominent horizontal striations.
Most commonly calcite forms tightly intergrown coatings of flat rhombohedrons, in many cases twinned, covering vast surfaces of sulfides (sphalerite, galena, pyrrhotite, pyrite) which are thus nearly totally hidden.
In most specimens of "normal" quartz which collectors are used to seeing, the prismatic crystals (whether single or twinned) rise from the matrix with the long crystallographic c axis more or less vertical, and are terminated by two alternating but usually unequal rhombohedrons.
Calcite is encountered very frequently in the Fengjiashan mine, a first generation occurring as squat rhombohedrons and a second generation as steep scalenohedrons.
The calcite crystals found in association with fluorite in the Xianghuapu mine are highly flattened rhombohedrons to 15 cm across.
In January 2006 the Mohodari quarry near Nasik produced a handful of spectacular large-cabinet calcite specimens, with lustrous, translucent yellow-brown rhombohedrons and modified scalenohedrons, reaching 15 cm individually, resting lightly on basaltic matrix.
It was found in vugs along the Plata vein on Level 190, in crystals to 3 mm showing the base and two rhombohedrons.