What is the difference between pumice and granite?

Answer 1

Though pumice and granite are both igneous rocks, they are very different. Pumice is of extrusive origin (which means it formed when magma reached Earth's surface) and granite is of intrusive origin (which means it formed below Earth's surface). Pumice has a vesicular texture and granite is phaneritic (or coarse grained).

Answer 2

Basalt is a dark coloured, heavy rock of more or less uniform composition. Pumice on the other hand is composed almost solely of volcanic glass material, well watered in its initial state inside the volcano. When ejected from the volcano, the included water flashes off to steam, and causes many bubble voids to form in the bulk material. Thus it is light weight (it will float), and generally white in colour. Much of the material will just form part of an ash cloud, but pumice will generally range in size from that of a small pebble up to that of a boulder.

Answer 3

Speed of cooling. Granite has relatively large crystals and cooled slowly. Pumice not only has tiny crystals but still has voids where gases were trapped as it boiled due to it cooling very rapidly.

Answer 4

Granite forms when magma cools slowly underground and forms relatively large crystals. Pumice forms when gas-rich lava is ejected into the air by a volcano and cools quickly to form porous glass with no crystals.

Answer 5

Though pumice and granite are both igneous rocks, they are very different. Pumice is of extrusive origin (which means it formed when magma reached Earth's surface) and granite is of intrusive origin (which means it formed below Earth's surface). Pumice has a vesicular texture and granite is phaneritic (or coarse grained).