beryl vs nephrite

beryl

noun
  • A mineral of pegmatite deposits, often used as a gemstone. 

  • A dull blueish green colour. 

  • An example (a stone) of the mineral beryl. 

adj
  • Of a dull bluish green colour. 

nephrite

noun
  • A semi-precious stone, one of the two types of stone commonly referred to as jade (the other being jadeite). 

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