illustrative vs quintessential

illustrative

adj
  • Demonstrative, exemplative, showing an example or demonstrating. 

quintessential

adj
  • Of the nature of a quintessence (in all senses); being or relating to the ultimate essence of something. 

noun
  • The fundamental essence of something. 

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