PMC stands for Precious Metal Clay. It is a fantastic new material that was developed in Japan. It contains tiny silver particles, a non-toxic organic binder and water. In this form it resembles clay and can be manipulated, rolled, pressed and stamped into just like a clay. Now here comes the clever part. Once you are happy with your design you let the clay dry out until the water has evaporated then it can be fired in a kiln or even with a hand held torch. All the organic binder burns off and the silver particles fuse together. Hey presto, it turns into pure (99.9%) silver.
There is a small amount of shrinkage (10% with PMC3) but other than that the design detail remains unchanged.