Theophrastus at this point. When Theophrastus says that water is colored by smaragdos, his statement apparently has a rational basis, for under proper conditions bright green stones do impart a greenish cast to the water in which they are submerged. The phenomenon is best seen when the illumination is oblique and the stone is placed in a small opaque white vessel. It is rather curious that the same property is not ascribed to precious stones of other colors, for these can also impart their color to water through reflection, especially when they are transparent and highly colored. However, few of the stones used for seals by the ancients were as brightly colored as smaragdos, and this may be the reason why the effect was noted only in the case of this one stone. It is possible, too, that Theophrastus may have based his statement on a single observation of smaragdos and that he did not attempt to experiment with other stones to see if they behaved in a similar way.
24. It is also good for the eyes, and for this reason people carry seals made of it, so as to see better. The verb βλέπειν without a preposition following it does not mean "to look at" but "to see," and some adverb like ev ("well") is really needed here for clarity. The meaning must be "to see better" or "to improve their sight." Pliny110 dwells at length on the pleasing green color of smaragdus and its supposed beneficial effect on the eyes. Though Theophrastus classifies smaragdos as one of the stones on which seals are engraved, Bliimner111 inferred from the wording of this particular passage that the allusion is to uncut ring stones. This conclusion is apparently supported by Pliny's statement112 that it was forbidden to engrave the surface of smaragdus. Since Roman emeralds were rarely engraved, Pliny's statement seems to be confirmed, and it is probable that he is speaking of true emeralds at this point.118 However, since no emeralds of purely Greek provenance have been found, it seems reasonably certain that Theophrastus is not alluding to emerald
110 XXXVII, 62-63.
111 Bliimner, Technologie und Terminologie der Gewerbe und Kiinste bet Griechen und Romern, Vol. Ill, pp. 241-42.
112 XXXVII, 64.
113 King, The Natural History of Precious Stones and of the Precious Metals, p. 298.
