ooid vs rectangular

ooid

adj
  • Shaped like an egg; ovoid; ovate. 

noun
  • A small calcium carbonate or iron coated grain found on the seafloor. 

rectangular

adj
  • Having a shape like a rectangle. 

  • Having axes that meet each other with right angles. 

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