This bracelet from Honestly WTF-DIY is so cute, and looks so easy to make. It is done with brass hex nuts and twine (or you could use leather cord). In the picture they show some chain attached — you could make it longer with a ball chain and close it with a brass toggle clasp from your local bead shop.
The brass washers are such a great idea, but you might find stone donuts that would work as well! The world is your oyster, yes?