I'm not sure how "green" this is, but take a look anyway. Paola Volpi uses humble and industrial materials to make refined, modern jewelry. It seems that most of her materials are new, but you can imagine applying her same approach to used or salvaged items, and then it gets really interesting. It's worth a spin through her portfolio.
The addition of fine jewelry details (pearls, clasps, fittings) pull it all together. I'm especially smitten with the use of oil filters and electrical wiring. Any way you slice it, the results are stunning.
Images from Paola Volpi. Via ecouterre.