bring out all its brilliancy, and this can only be done by a peculiar process, known but to few lapidaries, in which vitriol is employed. Theophrastus (c. 27), speaking of the Smaragdus, says, "There is a certain mode of working this stone so as to give it lustre, for in its native state it has no brilliancy." It is very likely that he has the Peridot in view in this passage, for in his age the coast of the Red Sea was the only source of the supply of the true Emerald, as well as of the Peridot or Topazion; which last, by the way, Pliny classes in his description as next in order to the Smaragdus. It was found in pieces of such size as to allow of a statuette of Queen Arsinoe, in whose time it was first brought to Egypt, to be carved out of a single gem. All these characteristics are combined in our Peridot, a stone on which I have rarely seen antique engravings, although such of modern times are sufficiently abundant. Its extreme softness probably deterred the ancients from using it for engraving upon, as it soon wears away when carried on the finger. It was highly valued still in Pliny's age, though somewhat fallen in estimation from the time of its first discovery, when it was preferred to all other gems.9 In compensation for this exchange of names the ancient I have, however, met with two Roman intagli, both figures of Minerva, upon this stone, and now possess a Medusa's head, cut in the bold, grand style of the period of its first introduction into Alexandria, in a large and very globose Peridot: an extraordinary gem, both for workmanship and rarity of material. Were it not for its softness this would be one of the most desirable of all gems as an ornament: by candle-light especially it has all the lustre of the Diamond, and appears of the purest water, its colour not being then discernible. The Chrysolite differs from the Peridot in being much harder, as well as of a yellower tint; for in it the yellow predominates over the green. In the Peridot green is the prevailing colour, modified by yellow: the stone, in fact, in the rough, much resembles a rolled pebble of bottleglass or Brighton Emerald. Chrysolithus is the present Topaz. The best kind is a yellow variety of the Ruby, of equal value and hardness with that gem, and very rare; Dutens values it at a third higher than the Sapphire. But most Topazes come now from Brazil; they are much softer, and of a different chemical composition from the Ruby; and besides the orange, there are white, red, and blue varieties of this stone, only to be distinguished from the Diamond, Ruby, and Sapphire by their much greater softness. The Chrysolithus was the only gem set transparent by the Romans, who seem never to have engraved it. All other stones were foiled with aurichalcum, i. e. a red foil of copper and gold. In confirmation of this remark of Pliny, I may observe that, on taking out a Sard intaglio from the oxidised remains of an antique iron ring, I found it backed by a thin plate of gold of a reddish colour, very different to the fine gold usually employed in ancient jewellery. Both Cellini and Winckelman have noticed this ancient practice of backing transparent intagli with a leaf of gold, which in fact shows off the engraving to greater advantage, when in wear, than if the stone according to the modern fashion were set open. Pliny mentions the practice of backing Carbuncles with silver foil, a method still used, and the best if the stone be of good quality. The use of coloured foils is a mere deception, and the sole end that the setter has had in view is to impose upon the unskilful by thus imparting to an inferior gem the finest colour of its own class. The Chrysoprase is an opaque, apple-green stone of a most agreeable hue, and extremely hard; its material is calcedony coloured by oxide of nickel. It is much of the same nature as the Plasma, but differs from it in the brightness of its tint, in its hardness, and in its opacity. Intagli are sometimes met with cut upon a stone which is either the true 10 Chrysoprase, or else a Plasma very nearly approaching to it in beauty. At present this gem is only found at Kosemütz in Silesia. TURQUOIS. This stone agrees pretty well with the description of the ancient Callais "which grew upon its native rock in shape like an eye, was cut, not ground into shape, set off gold better than any other gem, was spoilt by wetting with oil, grease, or wine, and was the easiest of all to imitate in glass. It was also the most favourite ornament of the Carmanians of that day,”—an observation equally applicable to the modern Persians, who lavish it in profusion over all their ornaments and weapons. Many supposed antique intagli and camei are shown cut in this gem; but I suspect the authenticity of all that have come under my inspection. From the rapid decay of this substance when exposed for a few years to the light and to moisture, there can be little doubt that any intaglio of Roman times executed in Turquois would long ere this have been reduced to a chalky mass. This actually is the case with such gems set in ornaments but a few centuries old, and which have lain underground for part of that period. The medieval notion concerning this change of colour was that the Turquois grew pale on the finger of a sickly person, but recovered its colour when transferred to a healthy hand. Another fancy was that its hue varied with the hour of the day, so that to the careful observer it could serve the purpose of a dial. In Germany it is believed that, when presented as a love-gift, its colour will remain unaltered so long as the giver is faithful, but will grow pale as his affection fades. The "fossil ivory mottled with dark blue and white," of 10 The true Chrysoprase is some- jewellery, set alternately with bits times found in antique Egyptian of Lapis-lazuli. Theophrastus, was our Occidental Turquois: in which the osseous structure is plainly discernible to the microscope, and which also is much softer than the true Oriental Turquois, or, as jewellers name it, that "de la vieille roche," which strikes fire with steel, while the Occidental can be scratched by steel. According to Hill, the blue which mottles the white surface of the latter can by means of heat be made to diffuse itself regularly throughout the whole, thus greatly improving its appearance and enabling it to be passed off for the precious variety. It is in this softer material that all the truly antique camei that I have seen have been executed, by far the best of which is a laureated head of Augustus among the Pulsky gems, and a Gorgon's head now in the Fould Collection. It is hardly necessary to add that the original azure of these gems, due to the oxide of copper, has been converted into a dull green by the action of the earth. MAGNET. On Magnet, a black compact and hard iron-ore,' I have seen rude intagli of the Lower Empire, especially of Gnostic subjects: the mysterious quality of the stone naturally pointing it out as a fit material for amulets. The Magnet was thought by the Romans capable of imparting knowledge in a case where ignorance is bliss, as appears from Orpheus, 312 : "If e'er thou wish thy spouse's truth to prove, If pure she's kept her from adulterous love, Within thy bed unseen this stone bestow, Muttering a soothing spell in whispers low: Though wrapped in slumber sound, if pure and chaste, But if polluted by adultery found, Hurled from the couch, she lies upon the ground." 1 This is the usual material of the cylinders of the purely Babylonian class. Dinochares, the architect of the city of Alexandria, had commenced the building of a temple in honour of Arsinoe, wife of Ptolemy Philadelphus, intended to be constructed entirely of loadstone, with the idea that an iron statue of the queen would, by the counterbalancing attraction of every part of the structure, remain suspended in mid-air; but the plan was never carried out in consequence of the death of Ptolemy. Here we have the origin of the medieval fiction of the iron coffin of Mahomet. Claudian, Idyl. v., thus describes a temple containing a statue formed out of loadstone, as actually existing in his own time, the end of the 4th century: "A stone there is which people magnet style, Of this deprived, its frame exhausted lies, Fierce hunger gnaws, and thirst consuming dries. With gilded ceilings decked a temple shines, And two immortals grace two common shrines; Mars scourging cities with his blood-stained spear, And Venus, solace sweet of human care. 2 The Roman antiquaries at pre- in a box of iron filings in order "to sent, whenever they meet with a loadstone intaglio, always preserve it keep up its strength." |