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! |
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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