While the necklace 's gemstones are believed to have been cut in India in the 17th century , the early history of the necklace itself is unknown . ; Sautoir or rope necklace A sautoir or rope necklace is any necklace longer than opera length . ; Uniform necklace A uniform necklace consists of pearls that appear to be all the same size , although normally there is a slight difference towards the ends so they appear to be in proportion .