Question

What type of rock is a pumice stone?
A) Sand stone
B) Limestone
C) Metamorphic rocks
D) Igneous rocks

Answer 1

Hint: Pumice stone is a light volcanic rock and additionally known as the magmatic rock. This rock is formed by cooling and solidification of lava or magma (molten rocks) and the rocks that form the pumice stone is the most basic rock.

Complete answer:
Now let us look into the given options:
Option A) Sandstone – Sandstone is a sedimentary rock. And sandstone is a rock and it is a mineral formed from the sands. Pumice is not formed from the sandstone and thus, this is an incorrect answer.

Option B) Limestone – Limestone is a type of carbonate sedimentary rock. They are composed of different crystal forms of calcium carbonate. Best example of limestone is dolomite. Thus, limestone is an incorrect answer.

Option C) Metamorphic rocks – These rocks are the transformation of the existing rocks. These rocks are formed when the rock is subjected to high heat, hot mineral rich fluid, high pressure etc., but this is an incorrect answer because pumice stone is not a type of metamorphic rocks.

Option D) Igneous rocks – Pumice stone is the type of igneous rock. Igneous rock and these rocks are formed when hot, molten rock crystallizes and solidifies and when this rock solidifies or hardens, a very light stone is formed with tiny bubbles of gas. Thus, this option is the correct answer.

Hence the correct answer is option ‘D’.

Note: Pumice stone is also called pumicite. The structure of stone is rough and it has many benefits such as it is used in removal of hair and used for scrubbing the body like it has beautification benefits. Pumice occurs because of simultaneous cooling and depressurization rapidly. And igneous rocks are formed by hardening the molten.