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BOOK I
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15
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human eye; aegophthalmos, a goat's eye; lycophthalmos, the eye of a wolf; astroites, the stars; lapis eislebanus, pike, perch, various marine fish, and even a cock and salamander; pontica, mountains
and valleys; agate and green marble, woods and streams. Under color of
minerals I have discussed those that have lines of various colors but
which do not resemble other things. Certain minerals are characterized
by small spots similar to the stars in the heavens and for that reason
are given the common name stellae. Lapis-lazuli, corallachates, and acopis have golden points, pontica, blood-red and black points. Lapis arabicus resembles
bones just as other minerals resemble hair. Clear, white marl resembles
the marrow of bones more than the outer portion.
Minerals
vary greatly in quantity. Some occur in large masses as do marbles and
rocks; others in small units, as certain stones and gems. Although
Nature has given all genera of minerals a small and discrete body,
nevertheless rocks, marbles, and earths often occur in great masses and
it is necessary to separate portions from the parent body.
Thus
minerals have differences which we observe by color, taste, odor, place
of origin, natural strength and weakness, shape, form, and size. In
order to make this knowledge clearer and more obvious, I shall explain
which genera are outstanding and most important and which, in general,
embrace all minerals.
Writers
do not agree on how many and which these may be. Aristotle states that
there are only two classes of bodies that form within the earth,
namely, minerals, which he calls ορυκτά, and those substances
from which metals are extracted and which he calls μεταλλευτώ. Others
believe that there are three classes, stones, metals, and earths, which
we cultivate. Avicenna mentions four classes, stones, stones that melt
in fire and which are called πηκτός by the Greeks, sulphurous
stones, and saline stones. Albertus places minerals in three classes,
stones, metals, and an intermediate class. Aristotle is seen to
classify subterranean substances in accord with the usage of the common
people of Greece. I am of the opinion that he named well-known earths
and even stones ορυκτά because they have only to be dug up and then they are ready for use and he called metallic materials μεταλλευτά because
it is necessary to smelt them. Irrespective of whether Aristotle bases
his classification on common usage or not, he fails to recognize that
metals are obtained from well-known earths and stones as well as from
minerals. Since it is commonly recognized that this is true, the genus
"mineral substance" embraces earth, stone, and metal. Even if we say,
in order to please some critics, that these substances have been named μίταΧλΐυτά. because
they are searched for and not because they produce metals, we are not
able to defend and support his classification even with this
interpretation. Since each is dug up the genus is "mineral substance."
These interpretations of his opinion have led us to the next theory. It
has been said that we search for metals deep within the earth with
little or no hope of finding them while stones and well-known
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