Precious Metal Clay (PMC Silver Clay and Gold Clay)
PMC Clay consists of microscopic particles of silver or gold suspended in an organic binder to create a pliable material with a consistency similar to modeling clay. PMC silver clay and gold clay both, can be worked with the fingers and with simple tools to create a vast range of forms and surfaces unobtainable or too laborious with traditional techniques. The PMC3 contains even smaller particles of silver, making it the strongest and lowest fired PMC clay product available.
When Precious Metal Clay is heated to high temperatures, the binder burns away and the metal particles fuse to form solid precious metal 99.9% pure. The metal can then be sanded, soldered, colored, and polished like conventional materials.
Here is a link that will tell you more.... I think it has been around since the early 1990s
http://en.wikipedia.org/wiki/Metal_clay