Another large piece worth mentioning is a jade sculpture dating from the reign of Qianlong in the 18th century. Entitled "Jade Mountain Showing the Great Yu Taming the Flood", it was sculpted after a Song Dynasty painting of a similar title. The masterpiece, standing 2.4 metres high and about 1 metre wide, depicts in vivid detail how the Great Yu, a heroic representative of the ancient working people, fought the Great Flood. According to historical records, the uncut jadestone weighing more than 5 tons, was discovered in Hotan area, Xinjiang. It took three years to be transported over the distance of l,000 kilometres to Beijing. After this, it took more time to carve and polish it into the national treasure that it is.

"There is a price for gold but no price for jade", says a Chinese proverb. Jade ware is often described as "worth a string of towns". An ancient story tells of how King Zhao of Qin who once offered 15 towns in exchange for the famous Ho's round jade. How is it that jade is so valuable?

First, its value lies in its scarcity. Precious stones are formed over long geological epochs and are hard to get, especially green jade, white jade and agate. Ancient people on a treasure hunt had to trek on the back of yaks in mountainous regions to get at the unhewn rocks containing the gems, exposed or half exposed by the stamping of the animal's hoofs. Sometimes, precious stones were washed down by mountain torrents and were got hold of midway by men with the eye and luck. In any event, exposed stones grew scarce and people began to bore through the mountains to mine for precious stones, making them even more difficult to get.

Secondly, the value of jade lies in its hardness. Precious stones are divided by their hardness into two major groups jadeites and nephrites. Jadeites are the ones with a solid texture and a hardness of degree 6 or above (on the basis of l0 for diamond). The more valuable varieties, such as green jade, may be as hard as degree 8 or 9. Jadeites are invulnerable to steel cutting tools made of carbonrundum or diamond power. Objects made of this hard jade are smooth, lustrous, glittering and translucent and their grains are no longer visible to the naked eye.

Nephrites, on the other hand being below degree 6 in hardness, can generally be incised and carved by buries. Their commercial values are much lower than jadeites.

Thirdly, the value of precious stones lies in their natural colour and hue. Some are as white as snow, others are brightly red and still others alluringly green. Diamond, emerald, saphire and other gemstones can be processed into personal ornaments like rings and earrings whose colour will remain brilliant all the time. Some stones carry an array of colours which a master artisan can use to good effect. Even flaws in the stone can be turned into "beauty spots", for instance, an insect on a flower or a small squirrel on a tree, adding life and attraction to the entire piece of work.

Today there are jade workshops or factories in all major cities. Work which used to be done purely by hand has been partially mechanized. Although some operations have become faster with the use of simple machines, jade carving remains basically a handicraft art. And as raw materials are getting more and more scarce, the prices of jade ware will always be on the upward trend.