Diamonds are cut into various forms, but principally into brilliants and rose diamonds. The brilliant cut is the most expensive and difficult, but is also that which best brings out the beauty of the stone, it has an upper or principal octagonal face, surrounded with many facets, and other things being equal, the greater the number of facets, the more valuable is the diamond. The lapi daries of the east, however, sometimes mul tiply facets to hide imperfections of the stone.
Rose diamonds have a flat base, above which are two rows of triangular facets, the six up permost uniting in a point. Rose diamonds are made of those stones which are too broad in proportion to their depth to be cut as bril liants. Stones still thinner are cut as table diamonds. The art of sawing diamonds, when too thick in proportion to their surface, was invented by a Dutchman named Dalbeck in the beginning of the 19th century.
The value of diamonds is variously esti mated. The rule generally given is to square the number of carats the diamond weighs, and then to multiply by the price of a single carat. Thus, a rough diamond of 12 carats one carat being estimated at £2, would cost 12 X 12 X 2 = £288. The value of a diamond is much increased by its being cut, although the actual weight is diminished.
Beyond a certain weight., no rule of calcu lation can be applied, owing to the limited number of purchasers, and the most fabulous values have been assigned to famous dia monds. The price of diamonds varies ac cording to the supply and changes in fashion, and is now lower than formerly.
There is a way of falsifying diamonds by joining an under part of some other stone to an upper part of genuine diamond. Some varieties of sapphire, hyacinth, and topaz, arc often passed off for diamonds. The first two may be distinguished by their greater specific gravity, the latter by its becoming electric when heated. Rock-crystal, and glass or "paste" imitations, are lighter than true diamonds, and less hard and brilliant. The best tIst of a genuine diamond is hardness. Care must be taken, however, to avoid breaking off its angles, in testing it by scratching other substances with it, as, though hard, it is somewhat brittle.
Some particular diamonds, from their unusual magnitude, or from circumstances of their history, are of such interest as to entitle them to notice. The collection of the emperor of Brazil is said to contain an uncut diamond—the Braganza diamond—of the enormous weight of 1680 carats, or about 12 ounces; but it is suspected to be only a fine colorless topaz.—The largest diamond certainly known is that belonging to the rajah of Mattan, weighing 307 carats. It is egg-shaped, with an indented hollow near
the smaller end. Many years ago, the governor of Borneo offered for it $500,000, two war-brigs fully equipped, a number of cannon, and a quantity of powder and shot. But the rajah refused to part with it, the fortunes of his family being supposed to be connected with it, and the Malays ascribing to water in which it has been dipped the power of healing all diseases. Perhaps the most famous diamond is the Koh-i-noor (q.v.), once a boasted possession of the great Mogul, and now belonging to the queen of Great Britain. It is said to have weighed 000 carats in the rough; but now, after various cuttings, weighs 123 carats. The Orlow diamond, belonging to the Russian emperor, and which was once the eye of an Indian idol, is said to have weighed, when rough, 779 carats, but is now cut, egg-shaped. and weighs 102} carats.—The Regent diamond, or Pitt diamond, which weights in its cut state 136f carats, is unrivaled in its limpidness and its form, its diameter and depth being nearly equal. It was found in Golconda, was brought from India by an .English gentleman named Pitt, the grand father of the first earl of Chatham, and by him sold to the duke of Orleans for £130,000. It decorated the hilt of the sword of state of the first Napoleon, was .taken by the Prus sians at Waterloo, and now belongs to the king of Prussia.—The Sandi diamond, weigh ing 100 carats, has a still more interesting history. It belonged to Charles the bold, duke of Burgundy, who wore it in his hat at the battle of Nancy, where he fell. A Swiss soldier found it, and sold it to a clergyman for a gulden. ft passed into the possession of Anton, king of Portugal, who was obliged to sell it, the price being 100,000 francs; and it shortly afterwards became the property of a French gentleman named Sandi, whose descendant being sent as ambassador to Soleure, king Henry III. required the diamond as a pledge; but the servant who was carrying it to the king was attacked by robbers on the way and murdered, not, however, till he had swallowed the diamond. His master, fully confident of his faithfulness, caused his body to be opened, and found it in his stomach. This diamond came into the possession of the crown of England, and James II. carried it with him to France in1688. Louis XV. wore it at his coronation.
In 1835, it was purchased by a Russian nobleman for half a million of rubles (£80,000). The Sand diamond is said to have been the first diamond which was cut in Europe.