Examples of Foliated Metamorphic Rocks

All three of the following rocks have the same parent rock: a sedimentary rock called shale that forms from mud and clay in environments such as ocean floors and swamps. When shale is metamorphosed to different grades it forms different types of foliated metamorphic rocks.

Rock

Picture

(click for larger image)

 Features Metamorphic Grade Other information
Slate

(Courtesy NPS)

 It looks like shale because it is dark in color and will break into thin flat layers like shale often does. Unlike shale, slate makes a ringing sound when you hit two pieces together. Low grade Used for walkways and patios.
Schist

(Courtesy NPS)

 There are several different types of schist such as mica schist, garnet schist, and chlorite schist depending on which minerals are abundant in the rock. The picture on the left shows a mica schist. However, all schist contains mica and often has rather large crystals of it. Intermediate grade Can you find the garnets in this picture of garnet schist?
Gneiss (pronounced "nice")

(Courtesy USGS)

 This striped rock often looks a bit like fudge swirl ice cream. The light colored layers are usually quartz and feldspar and the dark layers (the fudge!) are mostly mica. High grade The gneiss is nice in the Rocky Mountains! Check out these pictures of gneiss near Lake Isabelle!

Examples of Foliated Metamorphic Rocks

The three metamorphic rocks listed below all form from a sedimentary rock called shale. Shale is made from mud and clay in places like seafloors and swamps. When shale is metamorphosed to different grades it forms different types of foliated metamorphic rocks.
Rock

Picture

(click for larger image)

 Features Metamorphic Grade Other information
Slate

(Courtesy NPS)

 It looks like shale because it is dark in color and will break into thin flat layers like shale often does. Unlike shale, slate makes a ringing sound when you hit two pieces together. Low grade Used for walkways and patios.
Schist

(Courtesy NPS)

 There are several different types of schist such as mica schist, garnet schist, and chlorite schist depending on which minerals are abundant in the rock. However, all schist contains mica and often has rather large crystals of it. Intermediate grade Can you find the garnets in this picture of garnet schist?
Gneiss (pronounced "nice")

(Courtesy USGS)

 This striped rock often looks a bit like fudge swirl ice cream. The light colored layers are usually quartz and feldspar and the dark layers (the fudge!) are mostly mica. High grade The gneiss is nice in the Rocky Mountains! Check out these pictures of gneiss near Lake Isabelle!

Rocks With Wavy Layers Are Foliated Metamorphic Rocks!

Do you see the little wavy layers in the pictures of foliated metamorphic rocks below? All three of these rocks formed from a sedimentary rock called shale. With different amounts of metamorphism, shale becomes different types of rocks!

Rock

Picture

(click for larger image)

 Features How Much Metamorphism?
Slate

(Courtesy NPS)

 It looks like shale because it is dark in color and will break into thin flat layers like shale often does. Unlike shale, slate makes a ringing sound when you hit two pieces together. Low
Schist

(Courtesy NPS)

 There are several different types of schist such as mica schist, garnet schist, and chlorite schist depending on which minerals are found in the rock. All schist contains mica. Medium
Gneiss (pronounced "nice")

(Courtesy USGS)

 This striped rock often looks a bit like fudge swirl ice cream. The light colored layers are usually quartz and feldspar and the dark layers (the fudge!) are mostly mica. High


Page created September 16, 2003 by Lisa Gardiner.
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