Crystal Systems

Isometric (Cubic)

all 3 axes are equal length, all 3 axes are orthogonal

Tetragonal

2 axes are equal in length, all 3 axes are orthogonal

Orthorhombic

none of the axes are equal in length, all 3 axes are orthogonal

Triclinic

all 3 axes are unequal length, none of the 3 axes are perpendicular to another

Monoclinic

all 3 axes are unequal length, 2 of the axes are perpendicular to one another

Trigonal (Rhombohedral)

all 3 axes are equal length, no axes are perpendicular but all the faces have the same size and shape; sometimes not seperated from hexagonal system

Hexagonal

4 axes: 3 of them are equal length and are equally spaced out in the same plane while the 4th axis is perpendicular to the plane the other 3 are in