faience vs kaolin

faience

noun
  • A type of tin-glazed earthenware ceramic. 

  • The beads and small ornaments of the eastern Mediterranean. (Of bronze and iron age manufacture using frit technology.) 

kaolin

noun
  • A fine clay, rich in kaolinite, used in ceramics, paper-making, etc. 

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