quicksilver vs rocky

quicksilver

adj
  • Unpredictable, erratic or fickle; mercurial. 

noun
  • The metal mercury. 

  • An amalgam of mercury and tin applied to the backs of mirrors, quicksilvering. 

verb
  • To overlay with quicksilver. 

  • To treat with quicksilver. 

rocky

adj
  • Easily rocked; unstable. 

  • In the style of rock music. 

  • Abounding in, or full of, rocks; consisting of rocks. 

  • Like a rock; rigid, solid. 

  • Having a habitat around or on rocks. 

  • Encountering many problems; difficult, troubled; also, in danger or distress. 

  • Of a person: ill, or unsteady (for example, as a result of a shock). 

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