Tufa stone is a compressed volcanic ash material that is found on the Navajo reservation. It is easier to carve than sandstone and its porous surface leaves a unique texture once the metal has cooled. The artist’s design is carved into the flat surface on the inside of the mold. The negative space carved away will be filled with molten silver or gold.
Tufa stone is very fragile and most silversmiths will only get one good cast from each mold. Nearly all tufa cast pieces are one-of-a-kind as the mold will literally break after casting.