A Chinese Republic Silver Dollar Probably?

China- Yunnan Province- 50 Cents- Year 21 (1932) Y492. It is only .500 silver if it is real, and I have doubts- colour, and quality. These pieces are normally well struck (see the illustration in Krause). The "wear" patterns on this piece are quite incomprehensible- worn inside the rims on the reverse, with wear in patches across the design, and alternatively sharp and worn on the tassels, ribbons, stars, and even characters of the obverse. Listen to some .500 silver coins- Canadian quarters of 1968 in silver come to mind, to distinguish the sound of silver from the concoctions that are used in the modern Chinese Counterfeit flood- you can tell I suspect this is one of the bad ones. Also, silver does not normally turn that shade of blue-green.