bijou vs costume jewellery

bijou

noun
  • A piece of jewelry; a trinket. 

  • A jewel. 

  • A small intricate piece of metalwork. 

adj
  • small, little (often implying affection) 

  • intricate; finely made 

  • small and elegant 

costume jewellery

noun
  • Inexpensive jewellery, made of glass and other non-precious materials. 

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