This mirror is identical to a piece found in the Taklamakan, the "Desert of No Return" in Western China. That object is now in the Xinjiang provincial museum and was recently on loan in a special Silk Road exhibition at the Bowers Museum in Southern California, where it was dated to the 3-4th Century bce. a beautiful object in the hand, the ram atop this traditional mirror served as a handle and seems to have lost its horns in antiquity.

http://www.tmurrayarts.com/gallery-top/gallery/curiosity-cabinet/