Diamond
a precious stone. A form in which pure carbon occurs in nature. As a stone it is a crystal, generally without color, but found also in many tints and colors as blue, red, green, black, light yellow, straw, brown, pink, and orange. The diamond is the hardest substance known. It cannot be scratched by anything but a diamond. It cannot be dissolved by any known liquid nor melted under any attainable degree of heat. Any one who can afford to do so can burn a diamond, like a piece of coal, in oxygen. It consumes without ashes, giving off a brilliant light. When heated in a voltaic arc it crumbles into black lead.
Diamond dust is used in the arts to cut and polish gems. The edge of a diamond is used to cut glass, or rather in producing a scratch along which the glass breaks readily. A sharp diamond point is used in engraving on glass and steel, and, when set in a lathe, for turning glass lenses. Cheap diamonds are used in the diamond drill in making holes for blasting rocks.
As no tool will cut a diamond, the earliest method of dressing diamonds was that of grinding two diamonds together until the desired face had been formed. Under present methods, chips are split off until the stone approaches the desired shape. The faces are then held against a whirling disk of steel fed with oil and diamond dust, and rotated at a rate of 2,000 to 3,000 revolutions per minute. This method of polishing was hit upon shortly before the discovery of America. The chips are saved for many purposes.
Diamonds are cut into various shapes. The table stone is a flat slab-shaped gem with beveled edges. A rose diamond has a flat, circular, or elliptical under surface or base. Its upper surface consists of twelve or more triangular faces or facets, the uppermost of which come together in a point at the center. A third shape, the brilliant, gives the most sparkling effect. It is cut with facets on both the under and the upper surface. The top and back, however, terminate in flat facets instead of points. Counting these two central faces, the upper part of a regular brilliant has thirty-three faces and the lower part, or back, has twenty-five, making fifty-eight in all.
Golconda, India, was long a center of gem cutting. Amsterdam in later times has been the great European diamond cutting center. One Amsterdam establishment claims to cut and polish 400,000 diamonds yearly. America is the great retail diamond market of the world. About $525,000,000 worth, or one-third of the world's diamonds, are owned in the United States. Of late improved methods connected with the introduction of machinery have given American jewelers a claim to superiority in cutting as well. During the year of 1905 $36,060,000 worth of diamonds and other precious stones were imported into the United States.
Diamonds are widely distributed in nature. Small ones are found in a score of localities in the United States. The most ancient source of supply is India. In 1728 diamonds were found in Brazil, in 1829 in the Ural Mountains, and in 1867 the rich South African diamond fields began to attract attention. The richest diamond mines in the world are at Kimberley, South Africa, where a group of mines owned by a syndicate yields from ten to twenty million dollars' worth annually.
Diamonds occur in the shape of pebbles in beds of gravel, and are found by washing the earth. It is not uncommon for a diamond to explode on reaching the surface. Some have been known to explode in the pockets or in the warm hands of the miners. The larger the diamond the more likely it is to fly into pieces. Large gems are sometimes imbedded in a raw potato as a protection against explosion. Diamonds are weighed by the carat, 151.76 of which equal an ounce Troy. A perfect gem of a pure white without flaw is called a diamond of the first water.
Small artificial diamonds have been made by allowing carbon in molten iron to crystallize under high pressures, such as running the molten metal into a mold and cooling it quickly in cold water.
One of the most noted diamonds is the Kohinur or "Mountain of Light." After passing through various vicissitudes, including the sack of Delhi, it came into the possession of the East India Company, by whom it was presented to the English crown. It has been reduced by successive recuttings, the last in 1852, to a weight of 106.16 carats.
The Orloff diamond forms the point of the royal scepter of Russia. It is a fine rose diamond, weighing 194 3/4 carats. It was at one time the eye of an Indian idol at Mysore. Prince Orloff bought it through an Armenian merchant in 1772 for 450,000 silver roubles, and presented it to Queen Catharine of Russia.
The Regent or Pitt diamond is also from India. It weighs 136 3/4 carats, and is considered one of the most beautiful gems in existence. It is guarded as one of the treasures of the Louvre in Paris.
Of late astonishing finds have been made at Kimberley. The mine is 640 miles from Cape Town, a ride by rail of two days and one night. The mine itself is the crater of an extinct volcano. The general surface of the country is level. The crater is about 312 feet deep. Diamonds were found in the gravel. Workmen have dug 300 feet lower, so that the mine is now 612 feet deep. A blue rock is lifted to the surface by powerful machinery, and spread out on the grounds to dry. In the course of a year, under the influence of the sun, rain, and winds, it decomposes and falls apart. It is then crushed, washed and sifted, and passed finally over shaking tables, covered with a certain sort of grease that catches and retains the diamonds. These are then washed in an acid, sorted, valued, and sold to a syndicate. One thousand tons of blue rock yield 500 pounds of diamonds. The company employs 15,000 natives and 25,000 whites. Two hundred thousand horses are worked. A town of 35,000 people has grown up at the mine. At the end of 1904 it was estimated that diamonds worth $300,000,000 had been shipped from Kimberley. These gems would fill a box five feet square and six feet deep. The largest diamond produced at the Kimberley mine is one now known as the Syndicate. It weighed 960 carats in the rough. It is owned by Tiffany of New York.
The largest diamonds ever known have been found recently in the Premier mine at Johannesburg, South Africa. In March, 1905, a huge gem was found which was named the Culinan diamond. It weighed, uncut, 3,251 carats, or over a pound and a half. It was presented by the Transvaal government to King Edward. It was valued at $2,500,000. It has been split to form two large gems. These are known as Culinan I and Culinan II. They weigh 516 1/2 and 309 3/16 carats respectively. A second gem found since in the same mine weighs 460 carats. It is four times as large as the famous Kohinur. It is practically flawless. It is valued at $1,500,000.