radiance vs richness

radiance

noun
  • The quality of being radiant, shining, bright or splendid. 

  • The flux of radiation emitted per unit solid angle in a given direction by a unit area of a source. 

richness

noun
  • The state or quality of being rich; wealthiness, wealth. 

  • The result or product of being rich. 

  • The number of types in a community. 

  • The state of having many examples or cases; abundance; profusion. 

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