Hemihedraladjective
(of a crystal) Having only half the plane faces needed for the highest degree of symmetry in its system
Holohedraladjective
(of a crystal) Having as many plane faces as needed for the highest degree of symmetry in its system
Hemihedraladjective
Having half of the similar parts of a crystals, instead of all; consisting of half the planes which full symmetry would require, as when a cube has planes only on half of its eight solid angles, or one plane out of a pair on each of its edges; or as in the case of a tetrahedron, which is hemihedral to an octahedron, it being contained under four of the planes of an octahedron.
Holohedraladjective
Having all the planes required by complete symmetry, - in opposition to hemihedral.
