The Koh- i- Nur Diamond belongs to Queen Victoria, Empress of India. When Shah Shuja was driven from Kabul, he became the nominal guest and actual prisoner of llanjit Singh, who spared no means to obtain possession of this precious gem. In this he succeeded in 1813. After the death of Ranjit, it was occasionally wain by Kurruk Singh and Sher Singh. After the murder of the latter, it remained in the Lahore treaaury until the supersession of Dhulip Singh and tho annexation of the Panjab by the British. Upon the annexa tion of the Panjab, it was stipulated that the Koh i-Nur should be surrendered to the Queen of Great Britain. It arrived in London on the 30th June 1850, and on the 3d July was presented to the Queen. It then weighed 186 carats, and looked like a very precious gem. It was cut by M. Voorsanger of Amsterdam, at a cost of £8000. It was placed on tho mill by the Duke of 1Vellington on July 16th, 1852, to bo cut, and was completely finished on September 7th, having, taken thirty eight days to cut, working for twelve honrs per day without cessation. It was reduced to 106iir carats, and is valued at £100,000. It is a greyish stone, and, as jewellers say, too much spread, and was so very difficult to manage as to require to be twice cut. It has been suggested to bo the diamond, but Tavernier states the weight of that at 280 carats, and the Koh-i-Nur had only 186 before cutting.
Tho Brazil Diamond, calkx1 also the Great Bra ganza, the largest diamond known, belongs to the house of Braganza. When Dom John of Portugal (afterwards John vi.) arrived at the 13razils in 1808, a negro conveyed a letter to him, in whicl he professed an ardent desire to present, in person a large diamond which he had found. The regent granted him an escort, and the negro arrived am presented the stone. It is like a darkish-yellow pebble, kidney-shaped and oblong, about the SiZE of a pullet's egg. Its weight is over 11 ounces, ca 1680 carats. The Brazilian jewellers (Rome De lisle) value it at three thousand millions of cru sades, or 1300,000,000 ! but it is believed to be a white topaz.
The Star of the South of America, a stone ol singular beauty, was found by a negress in Brazil in 1853. It weighed 254 carats, but has been cut down to 125. It was sold for 13000, but 180,000 veere since realized for it from the Gaekwar of Baroda.
The diamonds of India are classed by native jewellers as white, yellow, red, green, and black ; the coloured ones are extremely rare, but they are occasionally found of a white colour spotted with red, which are rejected as bad. They are classed by the northern native jewellers into three kinds, —Hira-ba-rang-i-nausadir, greyish, or the colour of sal-ammoiaiac ; Hira makduni, of paler colour ; and Almas-i-hadidi. Hindus distinguish four kinds of diamond, differing from each other in beauty and value, called, 1. Brahma, 2. Kshatriya, 3.
Vaisya, and 4. Sudra,—names derived from the castes in which the Hindus are arranged. The Brahma diamond is described as of the colour of clear milk ; the Kshatriya, of clear honey ; the Vaisya, of cream ; and the Sudra, of a smoky greyish white.
Diamonds in the rough are unattractive pebbles. Even with those who profess to be acquainted with. precious stones, the white sapphire and topaz occasionally pass for the diamond. Some of the Ceylon diamonds which the Singhalese offer for sale are made of rock-crystal. The art of cutting diamonds is practised to some extent in India. A knowledge of this art, however, is not very common, as may be concluded when we mention that all Europe only possesses, in Amsterdam, one great diamond - cutting establishment, filled by workmen of the Jewish race, aud in London another. The diamonds seen in such abundance amongst the wealthy natives of India are almost all cut in Europe.
Diamond-cutting is effected by a horizontal iron plate of about ten inches in diameter, called a schiff or mill, which revolves from 2000 to 3000 times per minute. The diamond is fixed in a ball of pewter, at the end of an arm, resting upon the table in which the plate revolves ; the other end, at which the ball containing the diamond is fixed, is pressed upon the wheel by iron weights at the discretion of the workman. The diamond is cut by taking advantage of its cleavage, and also by abrasion with its own powder, and by friction with another diamond. It is a process of great labour, and many hours are spent in producing a single facet. They are cut into various forms, called the brilliant, the rose, and the table. The brilliant (brilliolette or briolette) form shows the gem to the best advantage, and is always set with the table upwards. In the rose the entire surface is covered with equilateral triang,le,s, terminating in a sharp point at the summit. This form is used when the spread of surface is too great for its depth, and it could not be cut into the brilliant form without great loss. The table is applied to , such diamonds as may be regarded as plates, laminm, or slabs of small depth compared to their l superficial extent. The brilliant and the rose lose r in cutting and polishing somewhat less than half the weight. In the formation of either a brilliant • or rose diamond, so much is cut away that the weight of the polished gem is not more than half that of the rough crystal out of which it was 6 formed. They were usually cut in the rose pattern till the middle of the 18th century ; but roses are, in general, only now used where the space in the setting prohibits the introduction of the brilliant form, brilliants being at present universally worn. The double cut brilliant is at present the common form. Diamonds were first cut in Europe in 1456 by Louis Berquen, a citizen of Bruges. .