Question

name the rocks that is used to write on blackboard​

Answer 1

Answer:

chalk

Explanation:

Answer 2

Explanation:

A blackboard (is also known as chalkboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulphate or calcium carbonate known, when used for this purpose as chalk.

Blackboards were usually made up of smooth, thin sheets of black or dark grey slate stone.