The tufa mold
Don’t be misled by the term tufa-casting to believe that once created, the mold will repeatedly produce multiple pieces of jewelry in the same pattern. Tufa, and the mold that is carved out of tufa, is a fragile material. Oftentimes, only one piece of jewelry comes from any single tufa mold. Even when a mold can be used more than once, the next pieces of jewelry to come from the mold will inevitably have variations.
Ira Custer tufa cast silver Double Naja, and the tufa mold used in the casting
Navajo silverworker Grey Moustache—who was interviewed by John Adair for his book The Navajo and Pueblo Silversmiths—speaks of the fragility of tufa casting: “…forty years ago (1898), when I made a trip up to Sunrise Springs. I saw some white rock on the side of a hill and I thought that it might make good molds for my silver, so I got some of it and made a cast for a ketoh. But that stone was too soft and cracked all to pieces. Then I went back a second time and got some more, and this time the stone was just hard enough, and I made a good ketoh in that mold.”