Buygemstone.net

It was common practice for the earliest Chinese jades to be carved from slabs a half inch or less in thickness. At this distance, it is difficult to know if the slabbing of jade was due to a shortage of material, difficulty in forming thicker objects, or just because of the fashion of the times. At the start, all jade cultures performed some sort of sawing or slabbing operation. Artifacts recovered in the Fraser River area of British Columbia show conclusively that the natives there successfully used a thin, flat slab of bedded sandstone to saw through jade. The process must have been appallingly slow and wasteful of jade, but it was effective. The jade piece was first sawed partway through on one side then flipped over and sawed partway through on the opposite side. The bridge between the two cuts was then broken by a sharp blow, saving untold hours of sawing. The exposed ragged edges could then be rubbed off to smooth the slab. The Maoris, Central Americans, and Chinese certainly used similar methods. Later, the introduction of the cord saw was a definite technical improvement. A cord drawn back and forth, as abrasive and water are fed to it, cuts hard stone surprisingly quickly. Even today the method persists, with wire taking the place of cord.
Only Chinese jade carving has continued to develop through the centuries to our own time. The art of the Central American lapidaries, although it flowered during the same period, suffered some for lack of good carving material, and then died abruptly with the arrival of the Spanish. Chinese carving development continued and eventually burst into its most frantic, ornate period in the 1700’s and 1800’s. Even the advent of the Chinese Communist state didn’t stop it. For a period of time the craft was outlawed, but it quickly returned to favor as a way of attracting foreign currency.