Found these today. I think they're silver plated. 13 stars. Trying to find how old they are. Still had a tiny bit of fabric attached, so assuming buttons, and not too old. Anybody know?
I believe these buttons first show up around 1938 with Army herringbone tweed (HBT) work uniforms. I'm hoping to find when they stopped using them. If like to know how recent they may be.
That form of button is called a rivet-button or tack-button, due to its construction. See photo below.
Your rivetbutton/tackbutton, showing 13 stars grouped inside a "sunburst" border, is from US Army herringbone-twill coveralls, in service from World War Two onward. See the other photo, showing one on the herringbone-twill fabric.
Edit-note: Archae33 and I were typing at the same time. Took me a few minutes longer, to find and add the photos.