The coin in our picture is a silver testone of Ludovico Sforza, duke of Milan (Mediolani) in Northern Italy from 1489 to 1508. It carries the coat of arms of Sforza with the characteristic snakes and eagles.
These coins are more common than one might think, and a quick search of the Internet shows many examples in various states of preservation. The coin in our picture comes from Ponterio & Associates and CoinQuest thanks them for use of their image.
Typical catalog values run like this:
average circulated: $500
well preserved: $1200
The item that Sal describes is different than this coin. It has many of the features of this coin, but not all. Since Sal's piece is mounted in jewelry, it may be a take-off from this coin, or it may be a coin that we are not familiar with. In any case, coins mounted in jewelry carry no collector value, so the best place for Sal to go is to a jeweler. (Sal, if you would like to send a picture, use the Contact Us link to start an e-mail exchange with CoinQuest).