Gold chain out of China.

Hello. I shall be leaving Shanghai Pu Dong airport in a few months wearing a 32.16g gold chain. I have the sales receipt and the box. I paid in RMB. What is the procedure for declaration? How much is the largest amount of gold I can take out of China? I read somewhere I need a 'special receipt' from the peoples bank of China. Is this true of will I be OK just wearing my chain strait through customs and declaring it to the officials?