WHAT ARE THESE? (BRASS RIVET BUTTONS)

[pooroldcancollector]

Found these in an old peanut butter jar. I tried searching brass buttons, which just brought me to a bunch of buttons, and I also tried rivets - This brought me to similar type hardware but nothing quite the same. Was showing me these nail/stud like split rivet things. Does anyone know exactly what these are or what they would be from?

PS... Please forgive the dirty looking photo! These are in a little container awaiting cleaning - they have a green tarnish/dust on them - and didn't I drop the container the other day!?! Had to scoop them off the shop floor

[KC]

These could be for 2 things! 
#1 are called Brass Rivets - look up jeans rivets.  They are hammered/pressed in at high stress areas on pockets, seams, etc.

or

#2  Decorative Dome Rivets for Upholstery - used for decoration and for high stress/pressure areas.