DIAMOND. (A corruption of ada mant). The most valuable of the pre cious stones. Diamonds were originally discovered in Bengal, and in the Island of Borneo. About the year 1720 they were found in Brazil. One lately found at Bahia was worth $225,000, though sold by the negro finder for $175. They always occur in a detached state in allu vial soil. The primitive crystalline form of the diamond is a regular octahedron, of which there are numerous modifica tions. Diamonds are found of all colors : those which are colorless, or which have some very decided tint, are most es teemed ; the latter, however, are rare. Those which are slightly discolored are the least valuable. The diamond is the hardest known substance, and can only be polished by its own dust or powder. The art of splitting or cutting and polish gem, though probably of remote antiquity in Asia, was first introduced into Europe, in 1480, by Louis Berghem, of Bruges, who accidentally discovered that by rubbing two diamonds together their surfaces might be abraded. They are cut chiefly into two forms, rote and brilliant : the latter have the finest effect, but require a sacrifice of a larger portion of the gem ; so that the weight of an or dinary polished diamond .often does not exceed half that of the rough gem. The largest known diamond is probably that mentioned by Tavernier, in possession of the great mogul; it was found in Gol conda in 1550; is of the size of half a hen's egg, and said to weigh 900 carats. The next most valuable diamond in the world has lately come into the pos session of queen Victoria, and was exhibited in the World's Fair. It was brought from the East and pre sented to the queen by the East India Company ; it is called the " Koh-i Noor" (Mountain of Light). All the na tives of Hindostan have heard of it, and it has had a mythological fame for a number of centuries. Its possession by any prince was superstitiously held to be the type of dominion. It was discovered in the famous diamond mines of Golcon da., but when is unknown. It was a state jewel of the Delhi Emperors until 1739. In that year the Persian warrior, Nadir Shah, conquered the Delhi mon arch, and carried away as his most pre cious trophy, the "Koh-i-Noor." It af terwards came into the possession of the Mears of Affghan, and was an heir loom in the family of Ahmed Khan Abdali, and was carried to Lahore by the fugi tive prince Shah Shooja, from whom it was extorted by the basest of means—.
starvation. This was the hospitality of the Sikhs. By the conquest of the 8ikh territory, in 1848, this diamond came in to the possession of Lord Dalhousie, ac cording to stipulation, to be presented to the queen. Its value is about eight mil lions of dollars ; it weighs 280 carats, and is of the finest water. It never has been in a dealer's hands, but has descended, either by fraud or force, from one prince to another. Its shape is like the pointed ;tali' of a hen's egg.
Among the crown jewels of Russia is a magnificent diamond, weighing 195 ca rats : it is of the size of a pigeon's egg, and was purloined from a braliminical idol by a French soldier ; it passed through several hands, and was ultimately purchased by the Empress Catharine for the sum of 90,000/. and an annuity of 4,0001. Perhaps the most perfect and beautiful diamond hitherto found is a brilliant brought from India by a gentle man of the name of Pitt, who sold it to the recent Duke of Orleans for the sum of 100,0001. It weighs about 186 carats, or 544 grains.
That the diamond is combustible was first proved by the Florentine academi cians in 1624, who found that when ex posed to the heat of the sun concentrated in the focus of a largo lens, it burnea away with a blue lambent flame. The proawcts of its combustion were first examined by Lavoisier, in 1772, who showed that when it was burned in air or oxygen it produced carbonic acid ; subsequent experiments have shown that nothing but carbonic acid is thus formed and hence it is proved that the diamond is charcoal or carbon in a pure and er,stalline form.
On the banks of the river Nikolaiefska, Tobolsk, in Siberia, in the midst of the auriferous send washings, has been dis covered a mine of stones resembling dia monds ; they are a little less heavy and hard, but are harder than granite. It is proposed to call them Diamantoid. Dia mond dust is used for working cameos, polishing brilliants, and sharpening cut lery.
Diamonds are valued by multiplying the square of their weight by the value of each carat. Allowing a rough diamond to weigh 4 carats, and the value of each carat is $8, then 4X4=16X8=$128, the value of a rough diamond. Manufac tured or cut diamonds, have their values found by doubling the weight—for ex ample, a cut diamond of two carats, dou ble the 2, thus 4)0=16 • multiply as be fore 16X8=128, the value of a eut dia mond 2 carats fine. are weighed by the carat of 31 graina Troy weight.