mauve vs purple dye murex

mauve

noun
  • A bright purple synthetic dye. 

  • The colour of this dye; a pale purple or violet colour. 

adj
  • Having a pale purple colour. 

purple dye murex

noun
  • A species of medium-sized predatory sea snail, Haustellum brandaris, which secrets a substance that can be used to make a long-lasting purple dye- Tyrian purple. 

How often have the words mauve and purple dye murex occurred in a corpus of books? (source: Google Ngram Viewer )