black as coal vs dusty

black as coal

adj
  • Completely black. 

dusty

adj
  • Grey in parts. 

  • Covered with dust. 

  • Powdery and resembling dust. 

  • Old; outdated; stuffily traditional. 

  • Ugly, disgusting (a general term of abuse) 

  • ugly, unwell, inadequate, bad (generally used in the negative) 

How often have the words black as coal and dusty occurred in a corpus of books? (source: Google Ngram Viewer )