The marbles are too well known to make it necessary for me to enumerate their several colours and varieties; and, indeed, so numerous are they, that it would be no easy task to do so. For what place is there, in fact, that has not a marble of its own? In addition to which, in our description of the earth and its various peoples,[2502] we have already made it our care to mention the more celebrated kinds of marble. Still, however, they are not all of them produced from quarries, but in many instances lie scattered just beneath the surface of the earth; some of them the most precious even, the green Lacedæmonian marble, for example, more brilliant in colour than any other; the Augustan also; and, more recently, the Tiberian; which were first discovered, in the reigns respectively of Augustus and Tiberius, in Egypt. These two marbles differ from ophites[2503] in the circumstance that the latter is marked with streaks which resemble serpents[2504] in appearance, whence its name. There is also this difference between the two marbles themselves, in the arrangement of their spots: the Augustan marble has them undulated and curling to a point; whereas in the Tiberian the streaks are white,[2505] not involved, but lying wide asunder. Of ophites, there are only some very small pillars known to have been made. There are two varieties of it, one white and soft, the other inclining to black, and hard. Both kinds, it is said, worn as an amulet, are a cure for head-ache, and for wounds inflicted by serpents.[2506] Some, too, recommend the white ophites as an amulet for phrenitis and lethargy. As a counter-poison to serpents, some persons speak more particularly in praise of the ophites that is known as “tephrias,”[2507] from its ashy colour. There is also a marble known as “memphites,” from the place[2508] where it is found, and of a nature somewhat analogous to the precious stones. For medicinal purposes, it is triturated and applied in the form of a liniment, with vinegar, to such parts of the body as require cauterizing or incision; the flesh becoming quite benumbed, and thereby rendered insensible to pain.