As a general rule, the rose diamonds sold for this purpose are sufficiently good for general work. In a very fine watch or chronometer the stone should be selected with reference to its polish on the face, and its parallelism in the lines of cleavage. The diamond, however, gets its great importance from being the only agent we can use in working other stones. Without it the whole art of jewelling would not be practicable. The various steps are all connected some way with diamond in its different shapes. “Bort,” the technical name for another variety, is merely fragments of the stone that have been cleaved off from a gem in process of cutting, or gems that have been cut, but found too full of flaws to become of use for ornamental jewelry purposes, the cost depending on the size, varying from $5.50 to $18 per carat. This “Bort” is used as turning tools--the larger pieces being selected and “set” in a brass wire and used on the lathe, in the same manner, and with the same facility, as the common graver. For tools, even the diamond is not of equal value--a pure white and crystalline in structure generally being too brittle (though hard) to endure the work. Among the workmen the “London smoke,” a clouded, brownish stone, is most prized--it possessing the twofold qualities of toughness and hardness. Another form of “Bort” comes in the shape of a small globule, sometimes the size of a pea; it is crystallic, and when fractured generally gives very small, indeed minute pieces of a needle shape. These are carefully selected, and form the drills with which the English hole-maker perforates the jewel. These drills, when found perfect, for soundness, form, and size, are very highly prized by the workman, as the choice of another, together with the setting, will often take a vast deal of time and labor. “Bort” is also used in the making of the laps or mills with which the jeweller reduces the stones to a condition for the lathe and subsequent processes. For this purpose such pieces as are not fit for cutting-tools, or drills, are selected. A copper disk, having been first surfaced and turned off in the lathe, is placed on a block or small anvil; each piece of stone is then separately placed on the copper, and driven in with a smart blow--care being taken that no place shall occur in the disk that does not present, in revolution, some cutting point. It would seem impossible to retain the diamond fragment, but it must be remembered that the copper, being a very ductile metal, receives the piece; the first rubbing of a hard stone then burnishes the burred edges of the indentations over every irregular face of the diamond, leaving only a cutting edge to project. The rapidity with which such a lap, well charged, will reduce the hardest stone, is somewhat marvellous. It is the first tool used in jewelling, and so important that a more detailed and explicit description of its make will be given when the process of manufacture is treated upon.