Francisco,
That is a TREASURE MARKER,,,No doubt about it!!! You are on the location....
Gboy,
These people who are digging may not lost anything as i said once again,,,THEY ARE ALL EMPLOYED,,, and simply using their spare time for their treasure quest,,,And im not going to encourage them to dig if i dont know that something is there!!! I believe MYSELF if what i can do to help them,,,thought this people never asked for financial assistance but their own strength and courage!...I dont like to discourage them as these people are WORKING OUT and NOT TALKING only....