HOW DIAMONDS ARE OBTAINED.—THE COUNTRIES THAT PRODUCE THEM.—MODES OF SEEKING THEM IN BRAZIL.—CURIOUS PRECAUTIONS AGAINST THEFT.—HOW A SLAVE IN BORNEO ROBBED HIS EMPLOYER.—FAMOUS DIAMONDS AND THEIR HISTORY.—THE REGENT, THE ORLOFF, AND THE KOHINOOR.—FIDELITY OF A SERVANT.—THE STAR OF THE SOUTH.—A SHARP TRICK OF AN AMATEUR GAMBLER. The hardest known mineral in the world, and at the same time the most valuable, is the diamond. It cannot be cut or scratched by any other substance. In cutting the diamond, another diamond, or the dust of one, must be used. The process of polishing these stones by rubbing two of them together was probably known in Asia a great many years ago; but it was not introduced into Europe until the middle of the fifteenth century. The diamond-cutters of Asia preserved the secret of their work very carefully long after these valuable stones were brought to Europe. About the middle of the fifteenth century, Louis Berquen, of Bruges, accidentally discovered that by rubbing two diamonds together, their surfaces might be cut. The powder obtained in this way is used for polishing the stone. The diamond must first be dug from the earth, and if we only knew where to find them we could doubtless discover richer gems than any of those now known. The earth which contains the diamond is worked in the same way as the auriferous gravels, both having been produced by the same causes. Gold occurs in the beds or streams, by the disintegration of the rocks, in which it was originally contained, and their gradual wearing and washing away. Diamonds were originally contained in the rocks in the same way that gold was held there, and the process of disintegration has been pretty much the same. Many of the places where gold is found contained diamonds; and in some localities in California the sands are now being reworked to obtain any small particles of gold that may have been left, and also to obtain diamonds. The original gold-seeker looked only for the yellow metal. The gold-seeker of to-day searches not only for gold, but for hard pebbles, which may prove rough diamonds. [Sidenote: WHERE DIAMONDS ARE FOUND.]