Detected my cornfield permission today. The good hits have slowed, but I was “real” happy to dig this Spanish silver, an 1803 1/2 real minted in Mexico City. It gave off a surprisingly loud tone on the AT Pro, especially for such a small coin. Also found what looks like a cut coin, but I can only make out a letter B, as shown in the top center of the photo. The key looks odd to me, and I have no idea of its purpose. Thanks for checking out my post. Good luck out there!