Waise, that is, the Orphan. But with the Italians the same stone went by the name of Girasole in virtue of its radiance when turned towards the solar beams.
No other gem was so successfully imitated by a glass paste (similitudine indiscreta) : the only test for detecting such being to hold them in the sun, when, if the false gems were poised upon the finger and thumb against its rays, a single colour showed through the mass -unchanged, and was spent within itself. In the real Opal, on the contrary, the colour perpetually changed, shooting forth now beams of one, now of another tinge, and diffusing their lustre over the fingers supporting it. Nothing shows the wonderful skill of the ancient glass-workers more convincingly than this testimony of Pliny's to the success in counterfeiting the Opal, a gem of which it has hitherto baffled the skill of the Parisian paste fabricant, to produce an imitation at all capable of deceiving the connoisseur.*
From its then enormous value, as well as on account of its fragile nature, the Opal must have been rarely submitted to the skill of the Roman engraver ; for the earlier Greeks were totally unacquainted with the gem. Hence Professor Urlichs justly pronounces unique the Opal of the (former) Praun Collection, engraved with the head of Sol between those of Jupiter and Luna. The somewhat debased style shows it to be a work of the Lower Empire, when the all-prevailing faith in astrology had sufficient
* It is, however, possible that Pliny hero alludes to the Girasol Calcedony, which greatly resembles a bad Hungarian Opal, exhibiting a flamy reflexion, but unmixed with green, and which the Romana doubtless considered as an Opal. This kind is indeed exactly and easily counterfeited in glass. Of something of the kind (or else of schmelze) were the glass opalescent cups (allassontes) sent by Hadiian to Servianus as specimens of the Alexandrian manufacture.