"The unit cell of a mineral is the smallest divisible unit of a mineral that
possesses the symmetry and properties of the mineral. It is a small group of
atoms, from four to as many as 1000, that have a fixed geometry relative to one
another. The atoms are arranged in a "box" with parallel sides called the
unit cell which is repeated by simple translations to make up the crystal.
The atoms may be at the corners, on the edges, on the faces, or wholly enclosed
in the box, and each cell in the crystal is identical. This is what was meant by
an "ordered internal arrangement" in our definition of a mineral. It is the
reason why crystals have such nice faces, cleavages, and regular properties." (Joe
Smyth, University of Colorado)

The dimensions of the unit cell give its volume and are calculated as
follows:

Where:
Cell Volume is in Angstroms^{3} Z is in Formula Units per Cell Molecular Weight is in grams/mole Den(Calc) is in grams/cubic centimeter
and 0.60225 is the Avogadro constant / 1.0 x 10^{24} - note: (10^{-8}
angstroms/centimeter)^{3}