chalybeate vs ironstone

chalybeate

noun
  • A mineral water containing iron, a voguish general remedy during the 17th-19th century. 

adj
  • Containing dissolved salts of iron. 

  • Tasting of iron, said of mineral water. 

ironstone

noun
  • Any ore of iron which is impure through the admixture of silica or clay. 

  • A type of vitreous pottery similar to stoneware 

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