Mineral substances vary greatly in color, transparency, luster, brilliance, odor, taste, and other properties which are shown by their strength and weakness, shape, and form. They do not have the variety of origins that we find not only in living matter but also in original matter. Moreover they have not been classified like the latter on the basis of the place where they pass their life since mineral substances lack life and with rare exceptions are found only within the earth. They do not have the differences in characters and actions which nature has given to living things alone. Great differences are not the essential features of minerals as they are of living and original matter.
Minerals have no dissimilar portions made up of similar materials. For example, a mineral we call “complex” nature forms from different kinds of simple substances, none of them dissimilar. The substances we call similar the Greeks usually call δνοιομερής while dissimilar substances are called ἀνομοιομερής. Many minerals form from a single species, a few from many similar species. For example, each unit of red ocher is red ocher; each unit of alum, alum; asbestos, asbestos; gold, gold. All species of earth, congealed juice, stone, and metal are composed of single species except certain stones which are composed of two or more species. These stones are recognized by the presence of spots, veins, and areas that glitter like the stars. They may imitate different things by color variations. Thus from the minerals that come to . . .