Crystal systems: Crystal systems are the reference used to describe the periodic patterns and morphology of crystals. They are composed of three non-coplanar imaginary axes or vectors "a", "b" and "c", intersecting at an "origin" point. There are seven types with different symmetry (triclinic, monoclinic, orthorhombic, hexagonal, trigonal, tetragonal and cubic), defined according to the relationships of the vectors and the angles they form to each other (crystallographic parameters).
Fig. 6. Axial lengths and angles of 7 crystal systems.
