If it's genuine, Frank, you have a valuable coin. Remember:
DO NOT CLEAN YOUR COIN. CLEANING RUINS VALUE.
The amazing coin in our picture comes from Stack's Bowers and Ponterio where it sold in a 2011 auction for $1400 US dollars. This gives you an idea of value. CoinQuest thanks Stack's Bowers and Ponterio for use of their coin image. It's an amazing coin.
The problem with all coins like this is the possibility of fakes. China encourages, or certainly does not discourage, counterfeiting of rare coins as a money-making industry. Too bad. It gives Chinese coin collecting a bad name.
If you can send pictures, Frank, we may be able to tell if you particular coin is real or fake. There is a side-by-side comparison with a known fake below. If there is a good possibility it is real, you should probably have your coin authenticated, graded, and encapsulated by a professional third-party grading service like PCGS, NGC, ANACS, or ICG. Do not use other services.