This Is A Real Challenge

I found this what I think is a button, on the ranch this week.
This appears to be a very old coin on obverse, and reverse has the "stump" button metal, which stands uo, about 3/6th tall.
This may be nothing, or, something of interest.
I cannot speculate, so, I'll let the pics do the talking.
Measures 3/4" diameter, 5/16th inches tall, measuring to the top of the
raised metal in the middle. Weighs 8.43 grams.
I think the rim may offer answers in this detective work.
Whatever this thing is, it was fun to find it, and, now see if can be identified.