costume jewellery vs jewellery

costume jewellery

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

jewellery

noun
  • Collectively, personal ornamentation such as rings, necklaces, brooches and bracelets, made of precious metals and sometimes set with gemstones. 

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