Glossary of Terms
Hexagonal
Any mineral that falls under the following specifications belongs to the hexagonal crystal system:
Four axes, three are equal in length and lie at an angle of 120° from each other. The fourth is either longer or shorter but must be at a right angle toward the other corners.
(See also Trigonal)
3D Animated Illustration of a Trapezohedron
Crystals kindly provided by
Smorf