Yes, its green! Art Clay & Precious Metal Clay (PMC) are recycled products which reclaim a variety of different metals.
Art Clay is manufactured in
Precious Metal Clay, PMC, is produced by Mitsubishi Materials of Japan. Microscopic particles of silver are mixed with a moist binder to create a material that has the feel and working properties of modeling clay. Unlike Art Clay is seems PMC is not 100% reclaimed and/or recycled and I'm finding it hard to find info on the exact make up of reclaimed materials for PMC.
I'll keep researching and if any one out there has any hard facts, I'd love to hear them!
For more info, check out these link