CURIOUS ALTAR OF POWALAWA INDIANS OF ARIZONA.
The ceremonial objects are grouped around a crystal of rock-crystal in the centre. (See page [254].)
Chalcedony
An ingenious though far-fetched explanation of the power attributed to chalcedony of driving away phantoms and visions of the night is supplied by Gonelli, writing in 1702. For him the source of this asserted power was to be found in what has been erroneously termed the alkaline quality of the stone. This dissipated the evil humors of the eye, thus removing the diseased condition of that organ which caused the apparitions to be seen.[63] However absurd this explanation may be, it nevertheless shows that the author put little faith in visible ghosts, and rightly enough recognized the purely subjective character of such phenomena.
Chrysoberyl
The cat’s-eye variety of chrysoberyl, or precious cat’s-eye, is used by the natives of Ceylon as a charm against evil spirits. As a proof of the high value set upon the gem in India, De Boot states that a cat’s-eye estimated as worth ninety gold pieces in Lusitania was sold for six hundred in India.[64] Some of the finest specimens come from Ceylon.
Chrysolite
The “Serpent Isle,” in the Red Sea, was stated by Agatharcides to be the source whence came the topaz (chrysolite); here, by the mandate of the Egyptian kings, the inhabitants collected specimens of this stone and delivered them to the gem-cutters for polishing.[65] These simple details are elaborated by Diodorus Siculus into the legend that the island was guarded by jealous watchers who had orders to put to death any unauthorized persons who approached it. Even those who had the right to seek the gem could not see the chrysolite in daytime; only after nightfall was it revealed by its radiance; the seekers then marked well the spot and were able to find the stone on the following day.[66]
From this Egyptian source, and possibly from others exploited by the Egyptians, have come the finest chrysolites (peridots, or olivines), the most magnificent examples of this gem. These found their way into the cathedral treasures of Europe, evidently by loot or trade at the period of the Crusades, and are generally called emeralds. Those most notable are in the Treasury of the Three Magi, in the great “Dom,” or Cathedral at Cologne. Some of these gems are nearly two inches long.