Deep within the Earth, molten rock, called magma contains water that is
prevented from becoming steam by the great pressure that exists there.
If magma reaches the earths surface where it is called lava, the sudden
reduction in pressure causes the water to turn into steam. When
lava solidifies and forms Pumice, countless tiny bubbles of steam are trapped
before they can escape. Most of the volume of Pumice thus consists of air
spaces. As a result, Pumice is so light that it will float on water!!.
Powered Pumice is used as an abrasive by dentists and industry.
is a grayish white natural glass with many holes.
is valuable in scoring, scrubbing, and and polishing material in both powered
form and in Pumice stone.
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