I have a bow, but no set of strings
I have a collar, but I'm not a pet thing
I have a stem, but I'm not from a pot
I have a blade, just not from Camelot
I am often scraped and dropped and abused
But not unkindly, I have my own use
I open what is precious, expensive or dear
Except for a pick, there is nothing to fear!
What am I?
This should tell all, I swing off a wall
Or end of a string, or inside a ring)