hard-boiled vs stone-hearted

hard-boiled

adj
  • Written in a laconic, dispassionate, often ironic style for a realistic, unsentimental effect. 

  • Cooked to a solid consistency. 

  • Callous and unsentimental. 

stone-hearted

How often have the words hard-boiled and stone-hearted occurred in a corpus of books? (source: Google Ngram Viewer )