detritus vs gangue

detritus

noun
  • Organic waste material from decomposing dead plants or animals. 

  • Any debris or fragments of disintegrated material. 

  • Pieces of rock broken off by ice, glacier, or erosion. 

gangue

noun
  • The earthy waste substances occurring in metallic ore. 

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