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Although no one knows the earliest techniques and tools for sure, rubbing-sticks of various designs, sand abrasive, and quantities of time and patience were all that the ancients seemed to use. Introduction of the rotary drill made it possible to add dimension and detail to the carvings, and to make hollow objects, such as vases and snuff bottles. These were— and are—always hollowed out before outside surface work on the carving begins. For turning the drill, the bow and the foot-treadle attachment are about the only mechanical improvements in this device in thousands of years. Since metal was introduced into Chinese technology centuries after jade had already been mastered, it had almost no real effect on methods of jade carving. Tools for sawing, drilling, and grinding became somewhat more efficient and less wasteful of jade. The earliest abrasive was probably quartz sand, which is almost always readily available. It is still widely used for many abrasive purposes. A switch from sand to crushed garnet, with its combination of superior hardness and sharp-angled grains, occurred centuries before the beginning of the Christian era. The chief gain was the time saved, but control of the shape and finish for each carved piece was reduced because of the greater cutting speed. Metal tools were introduced by the end of the Chou Dynasty, about 500 B.C. At this point the craft had matured, so that almost anything could be executed in jade.
After another fifteen or sixteen centuries, the next change in abrasive—from garnet to corundum—came about. As before, time-saving was the major gain. The final revolution in abrasives came at the very end of the 1800’s, when man-made carborundum, with its very superior cutting qualities, was introduced into China. Diamond powder would be even better and is often used for white gold wedding bands, but because of its cost it has had no impact on the native carving industry.