I think what you have is an 1854 Silver Dollar (there were no half dollars made in 1854). If it is a Silver Dollar dated 1854 it would be worth about $2000 in good condition. I suggest that if you would like an exact appraisal that you retype your question with its complete description. I also suggest that you ONLY sell it to a coin dealer. If you don't (i.e. You try to sell it on online) than you will not get even a fraction of its true value. One other thing, do NOT clean it if you do this it will become worthless.
