Is this a button?

[tryno2]

These seem almost to big to be buttons, 1 3/4 inch diameter.   The screw on the back would be pretty uncomfortable if used as buttons.   The only markings are G I and V in a circle.  Anyone have any info on them (I have 8 or 10)

[soh.maryl]

Looks like a stud.  And doesn't it appear to be something military like on a dress uniform?