These are marble magnets. They are made simply with magnets, clear glass "marbles" like for floral or aquariums, paper, of course, and clear silicone sealant. I doubt if the silicone stuff is acid free.
Does this project or one of it's images contain pornography, profanity, or other illegal or offensive material? If so, please report it and our moderators will come by and clean it up in a flash.
July 27, 2009