In China, the most reputable Green Jade Ring producing area is Hetian in Xinjiang Province. Hetian jade is so hard that it can scratch glass. It has often been found in very huge pieces. An example of this is the huge jade hill on which the grand scene of Yu the Great leading people to control flood is elaborately carved. It was 5,350 kg weight (11,795 pounds) when it was completed. Now this artwork is displayed in the Forbidden City.
Nephrite's robustness is due to the fact it contains tremolite. It also can be divided into several sub-classifications according to color: white, grey, green, topaz, and black jade.
Serpentine jade, or Xiu yu in Chinese, is mainly from Xiuyan County in Liaoning Province. Made of many different ingredients, it takes on various appearances: white, yellow, light yellow, pink, green, dark green, light green and so on. This type is usually coloured in various shades of green. Usually serpentine jade is semi-transparent or even opaque like wax.
Lantian jade is produced in Lantian County, north of Xian in Shaanxi Province. It was also among the most charming ancient jades, for its rigidity made it easier to be carved into decorations and jewelry by our ancestors. The hue is uneven in colors of yellow or light green.