My mother-in-law and her husband lived in Arizona for many years. During that time (about 50 years ago) they purchased quite a bit of Navajo jewelry. She gave us 3 pieces - an eagle bolo with coral and turqoise, a watch with coral, black onyx and turqoise on both sides of the band, and a turqoise necklace. I hear others talking of Navajo jewelry with the artists' signatures inscribed on the back. None of these have a signature.

Does all Navajo jewelry require a signature to have any value? As far as I can tell, these pieces are sterling silver.