and
also an account of the properties themselves. The system of
classification is another closely related portion of Mineralogy. It
gives an account of the order in which the mineral species are
arranged. A third and most important part of Mineralogy is the
physiography of the various species—giving an account of their
characteristic marks, and a description of their appearance or external
aspect and forms, their principal physical and chemical properties,
their mode of occurrence, with their geological and geographical
distribution, and their various uses, whether in nature or whether in
the arts, or as gems for ornamental purposes.