Origin of hexad
Examples from the Web for hexad
Here there is a plane of symmetry perpendicular to the hexad axis; there is also a centre of symmetry.
Perpendicular to the hexad axis are six dyad axes of two kinds and each perpendicular to a vertical plane of symmetry.
This is the hexad axis or hexagonal axis, for which the angle of rotation is 60, or one-sixth of 360.
There can be only one hexad axis of symmetry in any crystal (see figs. 77-80).
No other element is here associated with the hexad axis, which is uniterminal.