Skarn: Description, Characteristics, and Other FAQs

In this article, you’ll obtain answers to common questions about skarn.

What Is Skarn?

Skarn is a type of metamorphic rock that’s formed when heat and pressure change the composition of existing rocks.

This process can happen when magma from an intrusive igneous body comes into contact with a sedimentary or metamorphic rock.

Skarns can also form from the metamorphism of carbonate rocks.

What Are The Characteristics of Skarn?

Skarn is characterized by a coarse-grained or even pegmatitic texture.

The minerals that make up skarn are typically pyroxene, amphibole, garnet, and quartz.

These minerals are arranged in bands or layers that run perpendicular to the metamorphic foliation.

What Color Is Skarn?

The color of skarn depends on the type of minerals that make it up.

For example, a skarn that’s rich in pyroxene minerals may be dark green, while one that contains a lot of amphibole minerals may be black.

What Is The Hardness Of Skarn?

The hardness of skarn depends on the type of minerals it contains.

For example, quartz is relatively hard (7 on the Mohs scale), while pyroxene is softer (5-6 on the Mohs scale).

Is Skarn Valuable?

Some skarns contain deposits of valuable minerals, such as gold, silver, copper, and zinc.

These skarns are mined for these valuable metals.

What Is Skarn’s History?

The term “skarn” was first used in the 19th century to describe a type of metamorphic rock that contains a high concentration of iron-rich minerals.

The word “skarn” comes from the Swedish word “skarv,” which means “scar.”

This name was chosen because skarn often forms a scaly or bumpy surface.

What Are The Uses of Skarn?

Skarn has a few different uses.

It’s sometimes used as a source of iron and other metals.

It can also be used as a construction material and as a source of gemstones like garnet.

Where Is Skarn Found?

Skarn is found in metamorphic belts around the world.

These metamorphic belts are typically found near convergent plate boundaries, where two plates are colliding.

Skarn is also found in some collisional orogens, which are mountain ranges that form when two continents collide.

Is Skarn Foliated or Non-foliated?

Skarn is foliated, meaning that it has a layered or banded texture.

This texture is created by the minerals that make up skarn, which are arranged in layers that run perpendicular to the metamorphic foliation.

What is the Protolith of Skarn?

The protolith of skarn is typically a sedimentary or metamorphic rock that has been changed by heat and pressure.

A protolith is the original rock that is changed by metamorphism to form a new rock.

In some cases, the protolith of skarn may be an igneous rock, if it has been metamorphosed by contact with magma.

Is Skarn Intrusive or Extrusive?

Skarn is intrusive if it forms from the metamorphism of a sedimentary or metamorphic rock by contact with magma.

Is Skarn Felsic or Mafic?

The answer to this question depends on the minerals that make up skarn.

Skarns that are rich in pyroxene and amphibole minerals are typically mafic, while those that contain a lot of quartz and garnet are typically felsic.

Is Skarn Aphanitic or Phaneritic?

Skarn is typically aphanitic, meaning that it has small, unnoticeable grains.

This texture is created by the minerals that make up skarn, which are typically small and evenly distributed.

Is Skarn Volcanic or Plutonic?

Skarn is plutonic if it forms from the metamorphism of a sedimentary or metamorphic rock by contact with magma.

Skarn vs Porphyry (Compared)

Skarn is a metamorphic rock, while porphyry is an igneous rock.

Skarn forms from the metamorphism of sedimentary or igneous rocks, while porphyry forms from the cooling of magma.

Skarn is typically coarser-grained than porphyry.

Skarn vs Marble (Compared)

Skarn is a metamorphic rock, while marble is a sedimentary rock.

Skarn forms from the metamorphism of sedimentary or igneous rocks, while marble forms from the metamorphism of limestone.

Skarn is typically coarser-grained than marble.

Skarn vs Hornfels (Compared)

Skarn is a metamorphic rock. Hornfels is also a metamorphic rock.

Both rocks form from the metamorphism of sedimentary or igneous rocks, though the compositions differ greatly.

Skarn is typically coarser-grained than hornfels.

Hornfels is very soft (only a 2-3 on the Moh’s scale), while skarn is generally harder (depending upon composition, but can be 5-7).

What Is The Difference Between Skarn and Gneiss?

Skarn and gneiss are both metamorphic rocks, but they have different origins.

Skarn forms from the metamorphism of sedimentary or igneous rocks, while gneiss forms from the metamorphism of granite.

Skarn is also typically coarser-grained than gneiss.