Small silver grain [opgelost]

So I came across this little piece. I believe it is metal detecting find. Diameter is about 11mm. Recently I have started to think that maybe it is some kind of pre-coins currency the idea may sound crazy but I don't see it as a button or some other decoration element.

Please tell me your opinion about it, so I could move it from the mystery items to the place where it belongs

probably an old button

Yep, after changing tactics in searching , I found some similar buttons to this one . Probably I was hoping for Christmas miracle mystery solved

Idolenz , thanks for pointing the way