Granite Pegmatites

Posted on Updated on


058Walked across this ridge and it was loaded with quartz crystals. You can see the faint veins of white running through the granite. When I got back, I searched the web for “red granite with crystals” and this is what I learned.

What is Pegmatite?

Pegmatites are extreme igneous rocks that form during the final stage of a magma’s crystallization. They are extreme because they contain exceptionally large crystals and they sometimes contain minerals that are rarely found in other types of rocks.

To be called a “pegmatite,” a rock should be composed almost entirely of crystals that are at least one centimeter in diameter. The name “pegmatite” has nothing to do with the mineral composition of the rock.

Most pegmatites have a composition that is similar to granite with abundant quartz, feldspar and mica. These are sometimes called “granite pegmatites” to indicate their mineralogical composition.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s