Trigonal Dipyramid

Trigonal dipyramid (12-faced form) shows several elements of symmetry, i.e. center of symmetry, four mirror planes, three 2-fold and one 3-fold rotation axis. The three mirror planes and three 2-fold rotation axis cut and run along the crystallographic axis a₁, a₂, a₃. The remaining one 3-fold rotation axis run along crystallographic axis c and it is perpendicular to last minor plane. All planes and rotation axis are intersected in the center of the object/crystal, where the center of symmetry is located. The trigonal dipyramid is a typical form for the trigonal crystal system.