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.
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 &μοιομΐρτ\ϊ while dissimilar substances are called ίνομουομίρη$. 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 our notice we learn these differences
and are able to study their nature.
taste, odor, and qualities of minerals which can be perceived by touch
are most widely known because they are more easily recognized by the
physical senses than qualities such as strength or weakness. A great
many of these qualities are not known to everyone although those
qualities which are learned through experience are widely known. For
example, everyone knows that fire can be produced by striking flint
with iron. On the other hand miners not only know this but also that
fire will melt some varieties of flint, shatter others. Many people
know that lode-stone will pick up iron but only a few know that this
power is weakened and destroyed if the stone is immersed in an acid.
order to show the differences in minerals I shall begin by classifying
them according to color, then I shall describe the nature of each form.
Minerals vary greatly in color. Chalk, alum, asbestos, and Arabian
marble are usually white. Persian marble, quartz, silver, quick silver,
and tin are almost always white. Pnigitis, sory, smoky quartz,
and Lucullian marble are black. Melia earth and one of the Eretria
earths are ash-gray. Lapis lazuli and sapphire are blue. Chrysocolla
and smaragdus are always green while some chalk and atramentum sutorium may be green. Ocher and gold