Samya Ceramics puzzle

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Across
  1. 4. clay turns ceramic
  2. 5. formed from volcanic ash
  3. 10. percent that makes up Earth's crust
  4. 11. highly plastic, too slippery to use alone
  5. 12. brings down melting temp.
  6. 14. Occurs in combination with other oxides
  7. 16. one of four components of clay
  8. 17. clay found where it's formed
  9. 18. purest of primary clay
  10. 19. combination of silica
  11. 20. used to fire clay into pottery, giant oven
Down
  1. 1. SiO2
  2. 2. serves to color,decorate, or waterproof
  3. 3. glass former
  4. 6. percent ball clay can shrink as much as
  5. 7. main component of clay
  6. 8. what a chemist calls clay
  7. 9. easily shaped and molded
  8. 13. found away from where it is formed
  9. 15. found below coal beds, many impurities