candleholder vs iridescence

candleholder

noun
  • A device for holding one or more lit candles 

  • A person who holds a candle to assist another person who is working in dim light. 

iridescence

noun
  • Any shimmer of glittering and changeable colors. 

  • The condition or state of being iridescent; exhibition of colors like those of the rainbow; a prismatic play of color. 

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