Anyone know what this is?

[Nikollas]

I found this thing metal detecting and I have no clue what it is. Anyone have an idea?

 

[reddogpatch]

Appears to be part of a metal button, missing the back side..

 

[reddogpatch]

Here's one I found similar just two days ago here in Fla..
Sorry abt the old hammer head picture ?

 

[joee5]

Welcome from the Garden State

 

[edlynne]

Looks to me like it is a seat of a faucet where the rubber washer would screw into.

 

[cudamark]

Or maybe a base for a fridge magnet.