Thank you for submitting your item for appraisal. This appears to be a copper necklace manufactured by Renoir of California. The company, founded in 1946 by Jerry Fels, produced copper jewelry until the early 1960s. The problem with corrosion was solved by applying a lacquer, possibly Zapon lacquer. The estimate is based on similar sold or offered at auction. "Asking prices" in the trade can be higher and vary.