3. Topaz of the ancients had a green colour, which is never the case with the modern topaz. It was found in the island Topazios, in the Red Sea.[94] It is generally supposed to have been the _chrysolite_ of the moderns. But Pliny mentions a statue of it six feet long. Now chrysolite never occurs in such large masses. Bruce mentions a green substance in an emerald island in the Red Sea, not harder than glass. Might not this be the emerald of the ancients?
[94] The word topazo is said by Pliny to signify, in the language of the Troglodytes, _to seek_.
4. _Calais_, from the locality and colour was probably the Persian turquoise, as it is generally supposed to be.
5. Whether the _prasius_ and _chrysoprasius_ of Pliny were the modern stones to which these names are given, we have no means of determining. It is generally supposed that they are, and we have no evidence to the contrary.
6. The _chrysolite_ of Pliny is supposed to be our _topaz_: but we have no other evidence of this than the opinion of M. Du Tems.
7. _Asteria_ of Pliny is supposed by Saussure to be our sapphire. The lustre described by Pliny agrees with this opinion. The stone is said to have been very hard and colourless.
8. _Opalus_ seems to have been our _opal_. It is called, Pliny says, _pæderos_ by many, on account of its beauty. The Indians called it _sangenon_.
9. _Obsidian_ was the same as the mineral to which we give that name. It was so called because a Roman named Obsidianus first brought it from Egypt. I have a piece of obsidian, which the late Mr. Salt brought from the locality specified by Pliny, and which possesses all the characters of that mineral in its purest state.
10. _Sarda_ was the name of _carnelian_, so called because it was first found near Sardis. The _sardonyx_ was also another name for _carnelian_.
11. Onyx was a name sometimes given to a rock, _gypsum_; sometimes it was a light-coloured _chalcedony_. The Latin name for chalcedony was _carchedonius_, so called because Carthage was the place where this mineral was exposed to sale. The Greek name for Carthage was Καρχηδων (_carchedon_).
12. _Carbunculus_ was the garnet; and _anthrax_ was a name for another variety of the same mineral.
13. The _oriental amethyst_ of Pliny was probably a sapphire. The fourth species of amethyst described by Pliny, seems to have been our amethyst. Pliny derives the name from α (_a_) and μυθη (_mythe_), _wine_, because it has not quite the colour of wine. But the common derivation is from α and μυθυω, _to intoxicate_, because it was used as an amulet to prevent intoxication.