rivière vs sautoir

rivière

noun
  • A necklace of diamonds or other precious stones, especially one of several strings. 

sautoir

noun
  • A chain to which a pendant is attached, worn around the neck. 

  • A ribbon, chain, scarf, or the like, tied around the neck in such a manner that the ends cross over each other. 

How often have the words rivière and sautoir occurred in a corpus of books? (source: Google Ngram Viewer )