Calcium carbonate (CaCO3) is a common substance found in rocks, pearls, and shells. Senku creates it by crushing seashells and seaweed found on the beach into a fine powder.


Senku claims calcium carbonate is the most important thing needed for a technological civilization. He states for specific uses for it:

  1. Agriculture: Calcium carbonate powder can be combined with dirt to blow away hydrogen ions and "upgrade" soil.
  2. Construction: Cooking calcium carbonate with sand creates mortar, a simple building material.
  3. Soap: Calcium carbonate collected from seaweed can be combined with oil to create soap. Hygiene in a world without medicine is key to survival.
  4. Gunpowder: Potassium nitrate created from crushing seashells mixed with various other ingredients creates gunpowder.


  • Senku hides the fourth application of calcium carbonate (gunpowder) from Tsukasa, hoping to use it against him.
  • Calcium carbonate has numerous other applications, including the purification of iron, chalk, and adhesives.[1]




v  e
Prologue Saga Stone FormulaCalcium CarbonateCrossbowGunpowder
Stone World: The Beginning Saga
Stone Wars Saga
Source of the Petrification Saga
Community content is available under CC-BY-SA unless otherwise noted.