(Trapezohedral-hemihedral).
Here there are the full number of axes of symmetry, but no planes or
centre of symmetry. The general form {hkl} is bounded by eight
trapezoidal faces and is the tetragonal trapezohedron.
Examples are nickel sulphate (NiSO4.6H2O), guanidine carbonate
((CH5N3)2H2CO3), strychnine sulphate ((C21H22N2O2)2.H2SO4.6H2O).