Nancy Picton, who usually reserves her talents for designing American Indian jewelry, is now using them to help rescue old necklaces from oblivion. Pearls, beads, chains, whatever - once relegated to early retirement because they were too short - are given a second chance with Picton's handcrafted sterling silver bead extenders. Banded on each side with smaller sterling beads, these one-inch ovals attach with a hook and eye device to an existing clasp. Up to three of them will lengthen a neck-piece more than three inches, and no one will be the wiser, for that many remain unseen in back. But the extenders are attractive enough to drop front and center, so there are plenty of imaginative possibilities. Piction may alternate them with beads for an entirely new look or update old stones by randomly interspersing them with extenders, and at $1 each they are even cheap enough to have a whole strand as back-ground for your great-aunt's keepsake. Gold fanciers can elongate chains with the help of Picton's seven-inch fourteen-karat link bracelets ($9), which hook off and on in a flash and can be had half-price of jewelry. Or, as gold and silver prices soar, you may just want ot gather up enough extenders to display in a glass bowl for the present and to use for wampum on some far distant day.

Nancy Picton. Zia Indian Jewelry, Bethesda Square Shopping Center, 7549 Old Georgetown Rd., Bethesda. Open Monday through Satureay, 11 a.m. to 9:30 p.m.; Sunday 1 p.m. to 9 p.m. 986-0681.