There so many jewerls stores around the world... But honestly, the most beutiful necklaces that I have never seen are from Van Clef & Arpels, a french firm who borned in Paris circa 1898.
Pearls and Gold.
Emerald and Diamond necklace.
Rubies, Emeralds, Diamonds and Pearls.
Pearls, Diamond and white Gold. This one owned to Princess Grace.
Here HSH Princess Grace wearing the necklace. Photo taken by H. Connant in 1956.
Last Elizabeth Taylor wearing one of Van Clef & Arpel´s diamond necklace in the middle of 60s. She was a lover of jewerly during all her life. She also wrotte a book called "My Love Affair with Jewerly".
Van Cleef & Arpels Official Website.