Sometimes, precious stones were washed down by mountain torrents and were discovered by men with a sharp eye and more than a little 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 challenging to obtain. Second, the value of jade lies in its hardness. Precious stones are divided by their hardness into two major groups, jadeites and nephrites. 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. Third, the value of precious stones lies in their natural color and hue. Some are as white as snow, others are bright red, and still others alluringly green. Some stones carry an array of colors, which a master artisan can use to good effect. In Chinese culture, jade symbolizes nobility, perfection, constancy, and immortality.