gleam vs scratch the surface

gleam

verb
  • To be strongly but briefly apparent. 

  • Chiefly in conjunction with an adverb: to cause (light) to shine. 

  • To shine, especially in an indistinct or intermittent manner; to glisten, to glitter. 

noun
  • A bright, but intermittent or short-lived, appearance of something. 

  • An appearance of light, especially one which is indistinct or small, or short-lived. 

  • A look of joy or liveliness on one's face. 

  • An indistinct sign of something; a glimpse or hint. 

scratch the surface

verb
  • To barely begin; to see or do only a fraction of what is possible. 

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