Sidewalk chalk is made from calcium and sulfate, which makes calcium sulfate. One of the most common chemicals connected to calcium is called “carbonate”, and together they make calcium carbonate.

This reaction creates calcium carbonate crystals, which build up and fill in the cracks in the concrete. The crystal shape varies, from sphere to needle-shaped, and each shape is strong enough to ...

The bacteria and waste form calcium carbonate crystals that fill cracks in the concrete, significantly increasing its durability. This process utilizes domestic food discards and rotting fruits ...

Even some single-celled phytoplankton form plates around their body using calcium carbonate, which eventually contribute to the sediment ... and together they collected fish fecal pellets in the ...