I am half Chinese and I know Chinese people love jade and wear it because it is supposed to protect you from harm.
Also, most Chinese women wear a jade bracelet that is permanent on their wrist (what I mean is that they wear it for a long time and never take it off and their wrist gets bigger so it is difficult to take the bracelet off), and if the jade "likes" you then it turns greener and greener.
However if the jade does not "like" you, then it will never turn greener than the shade it is in.
My mum’s jade jewelery have turned greener and greener over the years, she told me that jade doesn’t "like" her younger sister and that is why her younger sister’s jade jewelery always stay the same shade of green and never deeper.
That is what I have heard.
The biggest one is the protection.
According to Chinese lore you wear jade and if you fall the jade breaks and takes the damage instead of you.
There are also these: *Prevents nightmares and eye troubles. *Is a remedy for spleen, kidney, and digestive ailments. *Makes men fertile. *Brings success in games of chance. *Brings rain. *Averts epilepsy. *Cures animal bites. *Jade placed on the eyelids or in the mouth of a dead person brings back their spirit to another life on Earth.
Here is a link that will give you some useful information on Jade and the Chinese culture: http://www.chinatownconnection.com/chinese_jade.htm