calcium carbonate vs limestone

calcium carbonate

noun
  • A colourless or white inorganic compound, CaCO₃, occurring as chalk, limestone, marble etc; reacts with acids to liberate carbon dioxide. 

limestone

noun
  • An abundant rock of marine and fresh-water sediments; primarily composed of calcite (CaCO₃); it occurs in a variety of forms, both crystalline and amorphous. 

  • Pertaining to or made of limestone. 

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