The Gagate is a fossil, bituminous substance, containing carbon and ethereal oil. It is jet. The Thracian-stone was similar to it; indeed, we suppose, a variety of it. The Gagate was used by the ancients as a test of epilepsy, and a restorative from hysterical fits. Galen gives an interesting account of his experience in the medicinal use of gagate and Thracian-stone, the result of which is, that he found gagate rather to weaken than increase the powers of the bitumen which he had picked up upon the shores of the Dead Sea; but that as a desiccant, it operated beneficially in the cure of sores, and that not only of recent, but also of sinuous ulcers. (De Simpl. ix.) He mentions that he could not discover the river Gagas in Lycia, from which, according to Dioscorides, this stone derives its name. (Ibid.) There is an interesting description of the Thracian-stone in a passage of Nicander quoted by Galen, under this head, Theriac. (45.) The Arabians who treat of it merely copy from the Greeks. See Rhases (Cont. l. ult. 399, 400), and Avicenna (ii, 2, 107.) Mesue gives a formula for an oil of gagate. (De Oleis, i.)
Aristotle suggests that perhaps the Magnet is animated. (De Anima.) To comprehend his reasons for maintaining this singular opinion, it would be necessary to understand his theory of motion, as fully exposed in his ‘Auscultationes Naturales.’ Lucretius, with considerable ingenuity, attempts to explain the manner in which the magnet attracts iron. (vi, 1000.) Plato (in Timæo) and Hippocrates (De Sterilibus) also allude to its attractive property. Galen recommends it in dropsies. Dioscorides, Galen, and the other Greek authorities treat of it in a very cursory manner, merely stating of it that it has the same virtues as the hæmatite. The Arabians, more especially Serapion, give a much fuller description of it, which at all events identifies the Magnetis or Heraclean-stone of the ancients with our loadstone, that is to say, the magnetic oxide of iron. It was used by the Arabians as an application to poisoned wounds. See Serapion (De Simpl. 394); Avicenna (ii, 2, 463.) It was used in the practice of medicine from the earliest date. See Hippocrates (De Sterilibus.) Ebn Baithar recommends it in pains of the head and feet, if taken hold of, and in cramps. He copies Aëtius. (ii, 25.)
The Arabian-stone is a species of white marble. It is recommended by Dioscorides for hemorrhoids and as a dentifrice. (v, 145.)
The Alabastrites is a thick concrete gypsum. See Kidd’s ‘Mineral.’ (i, 63.) Galen says of it, that when burned it is adapted for medicinal use, and that it is sometimes administered in a draught to persons affected with stomach complaints. Dioscorides speaks of its being applied externally in such cases along with wax; calls it discutient, and says it represses the gums. (v, 152.) It would appear that this article is the Lapis eburneus of Rhases, who calls it an astringent and dentifrice. (Cont. l. ult. i, 395.)
Geoffroy says that the Smiris is the Emery of the shops. It is held by the mineralogists to be a variety of Corundam. See Cleaveland’s ‘Mineral.’ (278.) A specimen of it, from the Isle of Naxos (which may be supposed a good representation of the ancient Smiris), was found by Tennant to consist principally of alumine, with small proportions of silex and oxide of iron. Dioscorides recommends it in looseness of the gums, and as a dentifrice; he ranks it with septic and caustic substances. (v, 165.)
The Stones in Sponges consist principally of the muriate of lime. They were much commended as lithontriptics. See Dioscorides, Pliny, Galen, and Avicenna.
The Ophites is a pellucid stone, so called from its serpentine streaks. It was that variety of serpentine called verde antico. See Jameson’s ‘Mineralogy.’ According to Dioscorides, it was useful as an amulet in the case of persons stung by snakes, and was also reported to be useful in lethargy and headache. (v, 161.) Galen holds it to be lithontriptic. (De Simpl. viii.) The Arabians copy from Dioscorides and Galen. See Avicenna (ii, 2, 406.)
The Ostracites appears to have been petrified oysters. Dioscorides recommends it in menorrhagia, in inflamed breasts, and spreading sores. (v, 164.) Galen also recommends it for clearing the cornea. (De Simpl. viii.) See in like manner Avicenna (ii, 2, 393.)
The Geodes contains iron, argil, and silica. It is nearly allied to the Eagle-stone, and hence it is often called the Bastard Eagle-stone. See Hill’s ‘Theophrastus.’ Dioscorides recommends it as an ophthalmic remedy, and as a liniment for inflammations of the mammæ and testicles. (v, 168.) Avicenna says the vapour of vinegar in which it is dissolved checks the flow of blood and cures hot aspostemes. (ii, 2, 398.)
Matthiolus confesses himself quite unacquainted with the Naxian Whetstone. Sprengel reckons it allied to the Smiris. Galen would rather seem to make it a variety of the Ostracites.