Is Pumice Felsic or Mafic?  (ANSWERED)

Yes, Pumice is felsic.

Pumice (known as pumicite in powdered form) is a volcanic rock composed of strongly vesiculated coarse-grained rock glass.

This article will discuss pumice, a volcanic rock, and provide useful information about why it is felsic.

Is Pumice Felsic or Mafic? (EXPLAINED)

What is Pumice?

Pumice is a felsic mineraloid consisting of silicates and aluminates.

Erupting, hot molten rock bursts from volcanoes, producing pumice.

Water and carbon dioxide gases dissolved in magma form bubbles with this sudden pressure reduction.

This is similar to how carbon dioxide bubbles form when you open a fizzy beverage.

A solid foam forms when the magma cools.

Chemical Properties of Pumice

Pumice is an amorphous aluminum silicate with a silicon dioxide content of 76% and aluminum oxide of 13%.

It is low in ferric oxides, sodium, potassium, and water content.

Physical Characteristics of Pumice

Pumice is a unique rock distinguished by its lightweight and low density compared to other stones.

Having a porosity of 64 – 85% by volume, pumice can float on water until its vesicles are filled, after which it sinks.

The holes in the rock can be divided into two categories.

Some are tubular, while others are essentially spherical.

Pumice can be found in various colors, but it is generally always pale in appearance.

White, gray, blue, cream, green, and brown are available.

Pumice has a softening point of 900 °C, a Mohs score of 6, and a pH of 7.2.

Uses of Pumice

Pumice is found in different products and has many commercial applications.

Here are some uses of this rock.

  • Personal skin exfoliants
  • Production of stone-washed jeans
  • Growing cacti and succulents because of the ability of pumice stone to retain water.
  • Abrasives in polishes, erasers, and toothpaste.
  • Production of cement and water filtration.

What does being felsic or mafic mean?

The silica content of the two rocks distinguishes mafic from felsic.

About 45 to 55% of the mafic rock is silica.

One of the most common examples of Mafic rock is basalt, which contains only 50% silica.

Felsic, on the other hand, has 70-85 % silica. Silica makes up 70% of graphite.

Several geologic factors influence the chemical composition of rocks (whether mafic or felsic).

These factors can provide information about the components of rocks formed in that area.

  • In terms of viscosity, the lavas that cool to form these rocks differ. Mafic lava has a low viscosity and is typically flowing. This is due to the high temperature at which these lavas erupt. Felsic lava, on the other hand, is more viscous. This is because the lava while erupting is at a lower temperature when compared to that of mafic lava.
  • Mafic rocks are created primarily by eruptive volcanoes at the bottom of the sea, whilst felsic stones are formed when lava from tectonic boundaries is cooled.
  • Mafic is abundant in heavy minerals such as magnesium and ferric. Felsic, on the other hand, is high in silica and aluminum.
  • Felsic is abundant in low-density minerals such as oxygen, sodium, and potassium. As a result, these rocks have a low density, in contrast to mafic rocks, which have a high density and are hence heavy.
  • Mafic rocks are dark green or greenish-black in color, unlike felsic stones that are light-colored.

Why is Pumice described as felsic?

Pumice is classified as felsic because it has properties that put it in that category.

Here are some of these properties.

  • High silica content: pumice is rich in silica minerals. This rock contains as high as 76% silica oxide.
  • Low density: pumice has a low density due to vesicles within the rock and also its richness in low-density minerals such as oxides of sodium and potassium.
  • Colour: pumice may have different colors, such as white, gray, or blue. They are mostly pale-colored.
  • Origin: pumice are found all over the world but they tend to form commonly near water bodies or underwater volcanoes.

What is the relevance of Pumice as a felsic rock?

Pumice rock’s felsic nature plays a role in the variety of practical applications that may be found for this rock.

Here are two real-world instances to illustrate my point.

  • Identification: The felsic character of this rock can be utilized to distinguish it from other rocks that are classified as mafic. It has a porous surface, is lightweight, and is pale in color. The fact that it is lightweight means that it floats on water, unlike other heavier rocks.
  • Uses: Pumice has a variety of applications due to its felsic rock qualities, which have enabled it to be used in a variety of ways. Its abrasive texture and frothy appearance have made it useful in a variety of applications, including skin exfoliation and the creation of polishes.


Pumice is a felsic volcanic rock that forms when hot magma cools and condenses around air bubbles.

Pumice’s felsic nature allows it to be used in a wide range of industries, including beauty salons, textile manufacturing, and cement and polish factories, among others.

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