Princess Shams Pahlavi, the elder sister of Mohammad Reza Shah Pahlavi, King of Iran, passed away in exile in California in 1996. She was president of the Red Lion and Sun Society, Iran's equivalent of the Red Cross.
Linda Lee Thomas, the wife of the legendary Cole Porter, was a beautiful socialite known for her sense of style. Porter was famous for his witty music, composed for Broadway musicals and Hollywood films. Linda Porter died in 1954.
Adele Astaire (1898-1981) was the older sister and first partner of Fred Astaire. The two began performing at an early age on Vaudeville and soon became a successful dance team. In 1916 they made their Broadway debut. Adele retired in 1932.
It is possible this necklace was given to Mrs. Cole Porter by Princess Shams Pahlavi on an official visit to Iran.