Oica is the barbarian name given to a stone which is pleasing for its colours, black, reddish yellow, green, and white. Ombria,3378 by some called “notia,”3379 falls with showers and lightning, much in the same manner as ceraunia3380 and brontea,3381 the properties of which it is said to possess. There is a statement also, that if this stone is placed upon altars it will prevent the offerings from being consumed. Onocardia3382 is like kermesberry in appearance, but nothing further is said about it. Oritis,3383 by some called “sideritis,”3384 is a stone of globular form, and proof against the action of fire. Ostracias,3385 or ostracitis, is a testaceous stone, harder than ceramitis,3386 and similar in all respects to achates,3387 except that the latter has an unctuous appearance when polished: indeed, so remarkably hard is ostracitis, that with fragments of it other gems are engraved. Ostritis3388 receives its name from its resemblance to an oyster-shell. Ophicardelon is the barbarian name for a stone of a black colour, terminated by a white line on either side. Of Obsian3389 stone we have already spoken in the preceding Book. There are gems, too, of the same name and colour, found not only in Æthiopia and India, but in Samnium as well, and, in the opinion of some, upon the Spanish shores that lie towards the Ocean.