While I was still living in the States I started collecting postage stamps from different countries all over the world. I've melted a piece of glass and layered the postage stamp behind. Then I've wrapped the pendant with aluminium or copper tapes and burnished with a metal spoon. Then I glue on a pendant to match the backing with the trusty E-6000 glue and voila.
UK- although you can't really see behind the swirly orange of the glass...this one didn't turn out that well.