Celtic Silver Bangle with Amethyst

This bangle looked really sad when I saw it in the store. It was almost black and the amethyst was so dirty, one could barely recognize it as such. I gave it a good cleaning and it came back to life.
I have searched on line for some information on this piece of jewelry but found only some flimsy reproductions of this style. This bangle is solid and relatively heavy. I have no idea how old it is but I would guess it is a vintage piece.

Thanks for looking:)