about 200 million years ago, the raw and materials of Jet carving were plants which growed thriftily, because of floodwater or lithosphere's variance led to it was buried in the groundwater bottom or mixed bedload, then as a result of passing through millions of years, owning to high temperature, chemical combination of mud because of subterranean pressure, and natural coal's efflorescence made plants because a kind of black crystal coal. However (one ton amount 1000 kilogram, English one ton (long ton) amount 2240 pounds), the coal bed of per ton was exploited to available raw material of jet carving, which only has 100kg. Therefore, these materials were non-reproducible resource.

Now The engraver hand-worked carved elaborately to various kings of fine decoration, for example animals, personality and figure of Buddha etc. Owning to special material, Jet carving is worth o f collecting.