from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Having eight plane surfaces.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having eight plane surfaces; thus, in the shape or form of an octahedron.
- adj. Of, or pertaining to octahedra.
from the GNU version of the Collaborative International Dictionary of English
- adj. Having eight faces or sides; of, pertaining to, or formed in, octahedrons.
from The Century Dictionary and Cyclopedia
- Having eight equal surfaces or faces.
Rutile is made up mostly of titanium dioxide with two rarer polymorphs anatase or octahedrite, which is a tetragonal mineral of pseudo-octahedral habit, and brookite, which is an orthorhombic mineral, the Doctor explained to her.
I think aragonite, olivine and ice have hexagonal crystals whereas diamond has octahedral.
Ever. I slip my hands through the holes and into gloves, and pick up the biggest rock I see, a perfect 5-carat octahedral crystal three times older than the human species, formed during the age of the mastodons.
With an arrangement of three orthogonal and three octahedral transducers, the complete stress state in a soil can be registered and principle stresses, normal and shear stresses and stress invariants can be calculated.
How much does it derive from the gems 'brilliant sparkle, the product of an octahedral crystalline structure that reflects light in just the right way?
The stacking of the tetrahedral and octahedral sheets in the chrysotile structure has been shown to yield three types of chrysotile fibers: clino-chrysotile: monoclinic stacking of the layers, x parallel to fiber axis, most abundant formortho-chrysotile: orthorhombic stacking of the layers, x parallel to fiber axispara-chrysotile: two layer structure, 180° rotation of two-layer structures, y parallel to fiber axis
In the octahedral layer (brucite), magnesium can be substituted by several divalent ions, Fe+2, Mn +2, or Ni+2.
In the case of chrysotile, an octahedral brucite layer having the formula (Mg6O4 (OH) 4) -4 is intercalated between each silicate tetrahedra sheet.
And that particular stone almost looks like the half of a diamond crystal, of an octahedral (ph) crystal.
In the large chamber beyond were three cylindrical assemblies of metal and crystal, more than a meter across and several meters long, glowing from within: at the core of each cylinder was an assembly of octahedral crystals, of a deep red-gold color.