For centuries the American Indians have been using the natural materials for jewelry the rest of us have just discovered.  There is virtually no medium that has not been explored and mastered by the Indians: jade, turquoise, stone, wood, fur, feathers and materials of all kinds from the sea.  Many of us were introduced briefly to Indian skills in scouting or elementary school but the jewelry we saw bore no resemblance to the real jewelry worn by our parents.  Times have changed.  The current craze for earth materials in jewelry leads us quite naturally to a real appreciation of Indian skill.  Hishi, for example, are small beads made from broken pieces of clam shell, drilled, strung and rotated against a rough surface until rounded.  Strings of antique Hishi now command a handsome price along with the hand-carved fetish animals made by the Southwestern Indians.  Sterling and turquoise needs no comment.