I made this choker a few years ago for a Halloween party.
I cut of and sew a piece of material from an old dress felt belt and measured it to the size of my neck leaving extra room to tie at the back (I didn't have a button or chain to add to the back)
Then i found some old costume earrings and pulled off the gems and sew them on.
Then you just put on and tie around your neck, i had long hair which hid the knot at the back.
And hey presto your done :) Hope you like it.