possible connection between what we now call electricity and magnetism.
30. hyaloeides. The name suggests some sort of glasslike stone, but it is mentioned by no other ancient author, and the very brief description given by Theophrastus is inadequate for certain identification. Various conjectures have been made by commentators. Hill,197 for example, supposed that it corresponded to the astrion of Pliny,198 whereas Werner199 suggested that it might have been moonstone, and Lenz200 that it might have been a natural glass. Stephanides201 believed that various reflecting and transparent stones might have been known by this name, particularly the lapis specularis of Pliny,202 which apparently included mica and selenite. Though it is quite possible that various materials of a glassy nature received the name υαλοειδή?, it seems unlikely that such soft minerals as these were included, for Theophrastus is speaking of a stone or igneous material upon which seals were engraved. The real objection to identifying it as one of the glassy minerals is that, with the important exception of the various forms of quartz, all of which appear to have been known by their own special names, practically no specimens of engraved gems executed in such minerals have come down to us. Therefore, it seems not unlikely that the name may have been given to the various glass pastes that were by no means uncommon as a material for seals at the time of Theophrastus. About ten per cent of the engraved gems of the Hellenistic and early Roman period that are listed by Furtwangler203 were executed in glass pastes of various colors. One objection to this identification is that Theophrastus would not be likely to list an artificial product like glass among stones of natural origin.
197 Theophrastus'; History of Stones, p. 80.
198 XXXVII, 132.
199 Cited by Moore, Ancient Mineralogy, p. 227.
200 Mineralogie der alten Griechen und Romer, p. 21. The specific identification given by this commentator is "bouteillenstein," or bottle stone, a peculiar green natural glass also called moldavite or pseudochrysolite.
201 The Mineralogy of Theophrastus, pp. 123-24. 202XXXVI, 160-62.
203 Furtwangler, Die antigen Gemmen, Vol. II, pp. 130-46, 153-73. This figure and similar estimates mentioned elsewhere in this commentary are not given by Furtwangler but are based on his descriptions of antique gems.
