durable vs solid as a rock

durable

adj
  • Able to resist wear or decay; lasting; enduring. 

noun
  • A durable thing, one useful over more than one period, especially a year. 

solid as a rock

adj
  • Extremely thick and heavy, so as to make it impossible to move. 

  • Very reliable and dependable 

How often have the words durable and solid as a rock occurred in a corpus of books? (source: Google Ngram Viewer )