166 DIAMOND are also "mixed" or less regular forms used to suit the shape of the stone ; aud even splinters of diamond of 5-^ carat are facetted. In all the forms the girdle ought to be perfectly smooth, as a rough edge often appears through some of the facets as a flaw, and injures the brilliancy of the stone. The value of diamonds is determined chiefly by their size, purity, colour, freedom from flaws or stains, and the skill with which they are manufactured. Their weight is reckoned by the carat, of four diamond grains, originally an Indian weight. In England the carat is estimated as = 3 ] 74 grains troy; but it varies in different places, being, according to Schrauf, in Amsterdam = 205*70 milli grammes, in Florence = 197-20, in London = 205 409, in Madras = 207 35 3, in Paris = 205 50, and in Vienna = 2 06 13. The usual rule is that the value of the stone increases with the square of the weight in carats, and assuming 8 or 10 as the value of a cut brilliant of first quality in water and shape, weighing 1 carat, a similar stone of 2 carats would be worth four (2 x 2) times 8 or 10, i.e. 32 to 40 ; one of 3 carats nine (3 x 3) times, or 72 to 90 ; and so in proportion. Fine brilliants, however, of the sizes most in demand sell much higher, or from 12 to 20 or more the first carat ; whilst roses and tables are of considerably smaller value, and rough or uncut diamonds, generally sold in lots, fetch only about 2 or even less, the value being further diminished in all cases where the stones are " off colour," that is milky or tinted, or imperfect in other respects. Still more important is the state of supply and demand, especially for the largest and most valuable stones, for which there are often very few purchasers, and their price is thus lower than the rule would imply. Even political events affect the price by bringing many into the market, as at the time of the first French Revolution. In 1873 Cape diamonds were stated to be worth yellows under 5 carats, 40s. to 50s. ; above that weight, 3 to 4 per carat ; pure white stones under 5 carats, 3 to 4 ; and above 5 carats, 4 to 7, or more according to form or lustre. Fig. 15 shows the size of i > 3 soon 100 G-irats Fia. 15. Relative sizes and weights of diamonds. set stones round the girdle, the line indicating their depth, and the numerals the number of carats they may be expected to weigh. smarkable Some diamonds are remarkable for their size or history. iniouda. The largest undoubted diamond is the Orloff in the sceptre of the emperor of Russia, weighing 194 J carats, and cut in the rose form, with a flat face below, resembling the half of a pigeon s egg. According to one story, it formed the eye of an Indian idol, and was stolen by a French deserter ; another is that it belonged to Nadir Shah of Persia, and on his murder came into the hands of an Armenian merchant, who brought it to Amsterdam. In 1772 it was sold to Count Orloff for the Empress Catherine for 450,000 silver roubles (90,000), with an annuity of 4000 roubles FIG. 16. Pitt diamond. and a title of Russian nobility. Second to it is the Ilegeot or Pitt diamond (fig. 16), bought by Mr Pitt, the governor of Madras, in 1702, for about 20,000. He brought it to .,- "" --.. London, had it cut as a bril- / liant at, it is said, a cost of 3000, and sold it in 1717 to the regent duke of Orleans, for Louis XV., for 2 million francs, or 1 30,000 ; but it is estimated to be worth fully twice that sum. At the time of the first French Revolution it was sent to Berlin, but re appeared in the hilt of the sword of state worn by Napoleon I. It is considered as the finest and most perfect brilliant in Europe. It weighs 136| carats, but originally weighed 410 carats, and the fragments split or sawn from it when cut were valued at some thousand pounds. The third in weight is the Florentine, or Grand Duke, as it is named (fig. 17). It is of a fine yellow colour, oblong, and cut in rose. It is said to have been lost by Charles the Bold at the battle of Granson, and found by a Swiss soldier, who sold it for a few pence as a piece of rock crystal. It afterwards belonged to the grand duke of Tuscany, from whom it passed to the emperor of Austria. Its weight is usually given at 139J carats, but Schrauf finds its exact weight 133-16 Vienna carats, and its specific gravity at 19 C. 3 5213. FIG. 17. Florentine. The Koh-i-noor (fig. 18), the largest belonging to the British Crown, has also a singular history, corresponding to that of the country of its origin. The Indian legend tells that it was found in one of the Golconda mines near the Kishna river, and worn 5000 years ago by Kama, one of the heroes cele brated in iheMahabharata. It passed through many hands to Baber, the founder of the Mogul dynasty, in 1526, and was shown by his successor in 1665 to Tavernier, the French tra veller. Fid. 18. Koh-t-iioor. He describes it then as of the shape of a half egg, and weighing 280 carats, having been thus reduced by an unskilled stone-cutter from 793| carats, which it once weighed. In 1739 it passed to Nadir Shah, the Persian invader of India, who gave it the name of Koh-i-noor, or Mountain of Light, and from his successors in 1813 to Runjeet Sing, the ruler of Lahore. In 1849, on the annexation of the Punjab to British India, the Koh-i-noor was also surrendered and presented to the Queen in June 1850. It was exhibited in the Great Exhibition of 1851, and then weighed 186^ carats, but has since been recut, with doubtful advantage, in the rose form, and is now 106^5- carats. Its lower side is flat, and undoubtedly cor responds to a cleavage plane. Hence it has been con jectured that it and the Russian Orloff diamond are portions of the original stone belonging to the Great Mogul, whilst a stone of 132 carats, obtained by Abbas Mirza at the storming of Coocha, in Khorassan, in 1832, may by a third fragment. This portion was long used by a peasant
as a flint for striking fire. The three united would have