paradigm vs touchstone

paradigm

noun
  • A pattern, a way of doing something, especially (now often derogatory) a pattern of thought, a system of beliefs, a conceptual framework. 

  • An example serving as the model for such a pattern. 

  • A set of all forms which contain a common element, especially the set of all inflectional forms of a word or a particular grammatical category. 

touchstone

noun
  • A stone used to check the quality of gold alloys by rubbing them to leave a visible trace. 

  • A standard of comparison or evaluation. 

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