CHAP. 51.—CERAUNIA; FOUR VARIETIES OF IT.
Among the white stones also, there is one known as “ceraunia,”[3197] which absorbs the brilliancy of the stars. It is of a crystalline formation, of a lustrous azure colour, and is a native of Carmania. Zenothemis admits that it is white, but asserts that it has the figure of a blazing star within. Some of them, he says, are dull, in which case it is the custom to steep them for some days in a mixture of nitre and vinegar; at the end of which period the star makes its appearance, but gradually dies away by the end of as many months.
Sotacus mentions also two other varieties of ceraunia, one black and the other red; and he says that they resemble axes in shape. Those which are black and round,[3198] he says, are looked upon as sacred, and by their assistance cities and fleets are attacked and taken: the name given to them is “bætyli,” those of an elongated form being known as “cerauniæ.”[3199] They make out also that there is another kind, rarely to be met with, and much in request for the practices of magic, it never being found in any place but one that has been struck by lightning.[3200]
CHAP. 52.—IRIS; TWO VARIETIES OF IT.
The next name mentioned by these authors is that of the stone called “iris;”[3201] which is found, in a fossil state, in a certain island of the Red Sea, forty miles distant from the city of Berenice. It is partly composed of crystal, and hence it is that some have called it “root of crystal.” It takes its name “iris” from the properties which it possesses; for, when struck by the rays of the sun in a covered spot, it projects upon the nearest walls the form and diversified colours of the rainbow; continually changing its tints, and exciting admiration by the great variety of colours which it presents. That it is hexahedral in form, like crystal, is generally agreed; but some say that it is rough on the sides and of unequal angles; and that, when exposed to a full sun, it disperses the rays that are thrown upon it, while at the same time, by throwing out a certain brightness[3202] before it, it illumines all objects that may happen to be adjacent. The stone, however, as already stated, only presents these colours when under cover; not as though they were in the body of the stone itself, but, to all appearance, as if they were the result of the reflected light upon the surface of the wall. The best kind is the one that produces the largest arcs, with the closest resemblance to the rainbow.
“Iritis” is the name of another stone, similar to the last in all other respects, but remarkable for its extreme hardness. Horus says, in his writings, that this stone, calcined and triturated, is a remedy for the bite of the ichneumon, and that it is a native of Persia.
CHAP. 53.—LEROS.
The stone called “leros”[3203] is similar in appearance, but does not produce the same effects. It is a crystal, with streaks of white and black running across it.
CHAP. 54.—ACHATES; THE SEVERAL VARIETIES OF IT. ACOPOS; THE REMEDIES DERIVED FROM IT. ALABASTRITIS; THE REMEDIES DERIVED FROM IT. ALECTORIA. ANDRODAMAS. ARGYRODAMAS. ANTIPATHES. ARABICA. AROMATITIS. ASBESTOS. ASPISATIS. ATIZÖE. AUGETIS. AMPHIDANES OR CHRYSOCOLLA. APHRODISIACA. APSYCTOS. ÆGYPTILLA.
Having now described the principal precious stones, classified according to their respective colours, I shall proceed to mention the rest of them in their alphabetical order.