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Pliny has given a pretty detailed description of the precious stones of the ancients; but it is not very easy to determine the specific minerals to which he alludes.

1. The description of the diamond is tolerably precise. It was found in Ethiopia, India, Arabia, and Macedonia. But the Macedonian diamond, as well as the adamas cyprius and siderites, were obviously not diamonds, but soft stones.

2. The emerald of the ancients (smaragdus) must have varied in its nature. It was a green, transparent, hard stone; and, as colour was the criterion by which the ancients distinguished minerals and divided them into species, it is obvious that very different minerals must have been confounded together, under the name of emerald. Sapphire, beryl, doubtless fluor spar when green, and probably even serpentine, nephrite, and some ores of copper, seem to have occasionally got the same name. There is no reason to believe that the emerald of the moderns was known before the discovery of America. At least it has been only found in modern times in America. Some of the emeralds described by Pliny as losing their colour by exposure to the sun, must have been fluor spars. There is a remarkably deep and beautiful green fluor spar, met with some years ago in the county of Durham, in one of the Weredale mines that possesses this property. The emeralds of the ancients were of such a size (13½ feet, large enough to be cut into a pillar), that we can consider them in no other light than as a species of rock.

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?

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.

14. The sapphire is described by Pliny as always opaque, and as unfit for engraving on. We do not know what it was.

15. The hyacinth of Pliny is equally unknown. From its name it was obviously of a blue colour. Our hyacinth has a reddish-brown colour, and a great deal of hardness and lustre.

16. The cyanus of Pliny may have been our cyanite.

17. Astrios agrees very well, as far as the description of Pliny goes, with the variety of felspar called adularia.

18. Belioculus seems to have been our catseye.

19. Lychnites was a violet-coloured stone, which became electric by heat. Unless it was a blue tourmalin, I do not know what it could be.

20. The jasper of the ancients was probably the same as ours.

21. Molochites may have been our malachite. The name comes from the Greek word μολοχη, mallow, or marshmallow.

22. Pliny considers amber as the juice of a tree concreted into a solid form. The largest piece of it that he had ever seen weighed 13 lbs. Roman weight, which is nearly equivalent to 9¾ lbs. avoirdupois. Indian amber, of which he speaks, was probably copal, or some transparent resin. It may be dyed, he says, by means of anchusa and the fat of kids.

23. Lapis specularis was foliated sulphate of lime, or selenite.

24. Pyrites had the same meaning among the ancients that it has among the moderns; at least as far as iron pyrites or bisulphuret of iron is concerned. Pliny describes two kind of pyrites; namely, the white (arsenical pyrites), and the yellow (iron pyrites). It was used for striking fire with steel, in order to kindle tinder. Hence the name pyrites or firestone.

25. Gagates, from the account given of it by Pliny, was obviously pit-coal or jet.

26. Marble had the same meaning among the ancients that it has among the moderns. It was sawed by the ancients into slabs, and the action of the saw was facilitated by a sand brought for the purpose from Ethiopia and the isle of Naxos. It is obvious that this sand was powdered corundum, or emery.

27. Creta was a name applied by the ancients not only to chalk, but to white clay.

28. Melinum was an oxide of iron. Pliny gives a list of one hundred and fifty-one species of stones in the order of the alphabet. Very few of the minerals contained in this list can be made out. He gives also a list of fifty-two species of stones, whose names are derived from a fancied resemblance which the stones are supposed to bear to certain parts of animals. Of these, also, very few can be made out.