colourable vs polychromate

colourable

adj
  • That can be coloured. 

  • Apparently true; specious; potentially justifiable. 

polychromate

adj
  • Composed of many colours 

noun
  • A salt or ion composed of multiple chromate groups 

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