They have few pearls and if at all any are present, are as large as the
grains of the mother-of-pearl.
About the birth of the mother-of-pearl, it is said that it is like the
mace leaf when newly-born. It then clings to the hulls of ships and
boats. It is large and progressively becomes petrified. It then settles
deep into the sea and later the pearl has its birth in the shell automatically. There is no relationship between rain and the birth of the pearl. This
is just like saying that husr is born on boats.
Nasr, following the current opinion of the people, has said that the
pearl has its gestation with rain and is then nourished by the oyster. It is
actually like the human saliva which is cleaned by swirling it in the
mouth. The argument given by these people is that, if there are more
frequent rains or if they fall beforehand, pearls are produced in greater
abundance that year, This is what Al-Kindi says from experience and
observation. The pearl is attached to the animal. When cut, only half of
it gets broken and cannot function either for adornment or ornamentation purposes. This, however, is the case when it is very strongly attached to the shell in which case one has to do a lot of rubbing and cutting.
If, however, the attachment is slight, it is easily detached from a piece
like itself and is used with stones similar to it. The pearl that enters the
flesh of the animal is movable and its layers go on progressively increasing and one layer appears over another, otherwise only experience would
show.
Nasr writes:
When the rain-drop falls upon a nacreous shell, it freezes. The shell
keeps on growing, while the drop that is admitted into its mouth,
rolls and becomes a good and wholesome pearl. The drop that falls
upon a certain angle becomes crooked and does not stay evenly in
that it rolls away from the saliva. Sometimes its obliquity is due to
the shell having pressed it. The effect of this compression upon it is
lasting.
The best pearl is the one that collects one layer upon another and
congeals to form a pearl. The pearl present in the black flesh of the
animal which is attached to both its sides would not be without
blemish.
Nasr has discussed the compression exercised by the shell and the
effects created by it. The material of the pearl is soft at the time, as is
the case with gold which has different forms within the soil. From these
it would appear that gold at the time of solidification was soft and moist
like flour. This is why it accepts the impressions and markings made by
the gravel whose support it seeks, and, when the water passes through
different routes, different shapes are assumed by it. As for Nasr's statement that the layers are one over the other, he probably implies that all
