Calcium carbonate

CaCO₃

Limestone, chalk, limescale and marble are chemically the same. They are all forms of calcium carbonate.

Limescale, Limestone, Chalk, Marble are chemically calcium carbonates

Think of calcium carbonate as being milk (calcium, Ca) on a car bonnet, along with items associated with calcium carbonate:

• Limes in the back of the car are singing scales (limescale)

• The wheels on the car are marbles (marble is formed from highly pressurised limestone)

• Chalk tyre marks on the road (chalk is mainly limestone)

• The car is swerving around a stone that looks like a lime segment (limestone)