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! |
Shop Windows to the Universe Science Store!
TES XXVI, 3 fall 2010
The
Fall 2010 issue of The Earth Scientist, focuses on rocks and minerals, including articles on minerals and mining, the use of minerals in society, and rare earth minerals, and includes 3 posters!
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