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Mica ("MIKE-uh") from Pegmatite

Mica is an amazing mineral!  It bends, and it peels into thinner and thinner pieces -- so thin that you can see through it.  Although mica looks like glass, it won't cut you.

The mica on the left formed as melted rock cooled slowly, far below the surface of the earth.

To learn more about mica, scroll farther down this page.

Mica as loose flakes and in chunks of pegamatite.
  
bulletHow to recognize mica
bulletOther rocks that look like mica
bulletSpecial things to do with mica
bulletWhere mica came from
bulletHow mica formed
bulletOther names for mica
bulletLinks to Websites about mica
  

How to recognize mica

bulletThick pieces look silvery.
bulletMica breaks into thin, flat, flexible flakes -- you can see light through them!
bulletMica is often stuck on or mixed with larger pink, white, and gray crystals.
    

Other minerals that look like mica

In our neighborhood, the only things that you
might mistake for mica are pieces of clear 
plastic and broken glass.
   

Special things to do with mica

Try to do these things with mica:

(Picture to come later) Peel it!
  
(Picture to come later) Bend it!
   
(Picture to come later) Look through it!

   

Where mica came from

Most big pieces of mica come from a type
of rock called pegmatite.  We think the 
pegmatite that we buy in our area came 
from the Rocky Mountains in Colorado.

Gray slate is made, in part, of tiny flakes of 
mica.  Mica gives slate a satiny look.

  

How mica formed

Mica formed as melted rock cooled slowly, 
far below the surface of the earth.  Other 
crystals also formed, like quartz and feldspar.  
The growing crystals interlocked to make a 
rock called pegmatite.

   

Other names for mica

We use the name "mica" for this mineral,
but it is also known by other names:

bulletThe type of mica that we found is known as "white mica" or "muscovite."
bulletPeople used big sheets of mica to make windows for furnaces and other really hot places.  When mica is used in this way, it's sometimes called "isinglass."
bulletThe mica we've found in our area comes in 50-pound bags of pegmatite gravel labeled "Royal Gorge."

 

Here are some ways to classify mica (by grouping it with similar types of rocks):
bulletMica is a mineral -- one of the building blocks of rocks like granite and slate.
bulletThe mica that we found was part of an igneous rock.

   

Links to Websites about mica

Encarta® Concise Encyclopedia article on mica:
< http://encarta.msn.com/index/conciseindex/29/02962000.htm?z=1&pg=2&br=1 >

Article on the mica group of minerals, with a link 
to more information on muscovite:
< http://mineral.galleries.com/minerals/silicate/micas.htm >

    


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Copyright 2001 Eric D. Gyllenhaal                                             Search this Site
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This page was created on May 6, 2001, and it was last updated on July 27, 2002.