THE largest and most magnificent squares of lapis lazuli which I ever saw, says Beckman, were those in the apartments of a summer palace near Petersburg, belonging to the Empress of Russia, the walls whereof were covered with alternate facings of amber, and of this costly stone, fetched hither from Thibet. The ancient Egyptians used it extensively for engravings, and it is not unfrequently made up into seals now-a-days, in spite of the contained centra or points (pyrites) which Pliny declares render it unfit for this purpose. All the engraved specimens, however, we have either purchased or seen are of very coarse work. Smalt, i.e. cobalt, purified by torrefication, and fused with potash and siliceous earth, produces a beautiful fine blue powder, which is very often sold for true ultramarine; similar frauds are also practised with a calcareous Armenian stone, tinged blue with copper, as well as with mountain blue or malachite, fluor-spath, and blue jasper; the colouring matter, however, of the genuine lapis (brought from that long range of mountains in Tartary, which extends to the Caspian Sea,) is not derived, as in any of the above cases, from salts of copper; it is a rarer and a much costlier substance; its price ninety years ago in Paris being five Napoleons per ounce. Large fortunes were sometimes amassed by those who first supplied it. An apothecary of Modena, in the beginning of the sixteenth century, made so much by preparing this costly powder, that his son, a too studious youth, was advised to remit his exertions, nor unwisely to injure his health, as one obliged to work for a maintenance; since without labour,' writes his friend Ricci, you are now possessed of an ample estate; you have farms, houses in town and country sumptuously fitted up, the furniture all your own; besides which you have a father who is as good as a hun

dred estates to you, whose skill in preparing ultramarine alone, to say nothing of other large proceeds from the laboratory, as he is the exclusive possessor of the secret, enables him to make pretty much what he pleases, and has already secured great wealth to himself and his heirs.'

TRANSPARENT QUARTZ, ROCK

CRYSTAL.

After the opaque jaspers, of which we have just been speaking, a class of transparent stones, called from their glassy clearness hyaline, and whether tinted or colourless, constituting but different forms of that beautiful and well known mineral, rock crystal, next claims our attention. The ancients, who held many strange notions of the genesis of stones-as that they grew like truffles and potatoes in the earth, and were distinguished by sexual peculiarities-entertained the belief that crystal (a word equivalent,' says Hesychius, ' to λαμπρον κρυος, clear ice) was in fact this very substance; being formed of certain celestial humours, viz., of rain and small snow intimately mixed together, and afterwards congealed by a very hard frost, so that it could never again recover its primitive liquid form. Pliny, who adopts the same opinion concerning the production of crystal, observes, it is singularly confirmed by the extreme cold of those regions where it is known to occur, and instances the top of the Alps, where, like most theorists, he had the support of some facts in his favour; one of the gîtes of this mineral being the heights of Mont St. Gothard, where it yet abounds, might have given weight to his opinion, did not crystal also occur in much greater abundance and luxuriance in the Island of Madagascar, where this glacial hypothesis must of course melt before the tropical sun. It was not, however, all the ancient world that adopted this fancy; Diodorus Siculus gives a decidedly Vulcanist's view of its for

mation, saying, that though it is indeed water reduced to infusible ice, that this change is effected, not by means of cold, but by a very potent celestial fire, which, while it fixes, communicates to the solidifying mass all the beautiful tints in which it abounds. Both hypotheses suppose the water of crystallization (which modern science recognises as a true constituent of all crystal) to be the sole ingredient

in this.

Pliny describes very accurately the primary form assumed by this mineral, though he is fain to wonder how the six sides of the crystalline prism should be so planed and polished by nature that no art can reach them.*

While the common prefix of the word 'rock' to this particular stone correctly indicates one of its normal sites, there can be no doubt that it is also found disseminated in the ground where no rocks are near; still, though it may not be correct to confine these crystals absolutely to stone quarries, there is every probability that when found elsewhere they have originally been embedded in rocks and afterwards removed thence, and carried to a distance by the agency of water; hence our lapidaries distinguish two kinds-viz., spring crystal and pebble crystal. The first is lodged in the perpendicular fissures of strata ; commonly in hexangular columns, broadly adhering to the matrix at the base, and terminating at the other end in a point; the second occurs strewn at random in the earth, or amidst loose gravel, and is of no more determinate shape or size than common flints or pebbles. These polymorphic masses, however, are never the mineral in its first form as detached from the rocks, but have acquired a rounded shape from rolling about, and rubbing sides. with other stones.

Surgeons in the olden times were

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indebted to rock-crystal for a very notable way of applying the actual cautery; the practice was to hold a globe of crystal between the sun and that part of the patient's skin which they wished to burn, and provided he remained quiet and Phoebus (ExBoλos) did not withdraw his rays whilst the process was going on, they always had the satisfaction of grilling him, like an Aphys,§ in a very short time.

Crystal was immensely admired and used by the ancient world, both for intaglios and in the fabrication of costly vases. Theophrastus mentions it with the amethyst, both being diaphanous, and employed for seal engravings.' The number of engraved stones which occur in white or tinted rock-crystal are very considerable, and there can be no doubt that many of the gigantic ancient gems, rejoicing in the names of emeralds, amethysts, topaz, &c., were only rock crystal, coloured green, yellow, or blue, by different metallic salts. It is probable that in the words cited above from the Greek lithologist, that his amethyst was but a tinted modification of colourless transparent quartz; probability is all we can have here, since with the ancients one and the self-same stone changeth its name, not only according to the sundry spots, marks, and veins, &c., that arise in it, according also to the manifold lines drawn on it, and the diverse veins running between, but also according to the variety of colours therein observed, none of which accidents, however, makes any real difference.' The glories of rock crystal are not to be seen exhibited in full splendour in the small intaglios borne on the finger, pretty as some of these undoubtedly often are; but in those magnificent colossal boozing cups and vases with which the ancient Romans used to deck their rooms, many noble unsepulchred specimens of which now adorn

+ Pliny.

Hill.

colour; in the former the colour is generally more or less mixed and adulterated with other tints. A tawny agate, which has no distinctive modern name, but which may easily be identified with that called by Pliny A. leonensis. The dendritic, or tree agate,* of which pretty specimens occur occasionally along our own coasts; the mocha,t or moss-agate, which displays mimic mosses, lichens, and various byssoid growths so exactly portrayed that they used to pass for these cryptogamic substances, enclosed in the stone like flies in amber.

Agates not only imitate mosses and beehives, but in many places they have flowers imprinted on them, like to those which grow by the high-way, and paths, and fields; and they also assume many other yet stranger appearances; for you shall find the forms of rivers, woods, and labouring horses imprinted naturally in them: a man shall see in them coaches, and little chariots, and horse-litters, together with the furniture and ornaments belonging to horses.+

Sometimes nature impressed animal, and even human forms and figures on Oriental agates. Pyrrhus was the possessor of one of the most famous in ancient or modern records. This king of Epirus wore on his finger an agate, whereon nature vying with art, and as if determined to eclipse her in her own province, had placed Apollo with his harp and the nine Muses with their several insignia, the whole harmoniously grouped and faultlessly finished, even to the minutest details. Many modern authors report to have seen natural paintings upon these quartzes almost as marvellous as that of Pyrrhus, though not so charged with figures. Aldrovandi

had seen a very perfect Madonna and Child thus depicted, and those who are curious to know all the deceptions practised by agates on the human eye, will find in Panciroli all that has been seen, feigned, or fancied. Besides these and a variety of ribboned, zoned, and eyed agates, known both to the ancient and modern world, Pliny has described, under the name of lapis enhydros, a white semi-transparent pebble which, when shaken, is seen to be traversed throughout its cancellated structure by a liquid like the glaire of an egg. These stones can be none other than those small globes of chalcedony found in the neighbourhood of Vicenza, which are polished and made up into rings, the water from the little chambers occasionally escaping during the process of setting. The haminites, that Pliny describes as like the spawn of a fish, is an agate of which Corsi has seen ancient specimens at Rome, thus establishing the fact that there is a quartzose as well as a calcareous oolite.' Fine agates are found in many European countries, but the preference, as usual, is always given to the Oriental kinds; Sicily, however, which has been supposed to have given its name to the agate, from a river, anciently called Achates (now Drillo or Del Noto) produced, and yet produces very beautiful specimens; with these the ancient world were well acquainted. One of the staterooms in Hiero's famous ship was lined with them; and we know of none more beautiful than those obtained near Palermo, which are there offered in large quantities for sale, cut into various ornaments, but principally into knife and fork handles.

Pliny.