Yosemite at a Glance:
Geology

Intrusive rocks crystallize from magma that moved through surrounding rock. We don't see intrusive rocks until they are exposed after erosion and uplift. These can appear as large volumes of the igneous rock called granite.

Geology
Waterfalls

Granitic Rocks

Over 95% of the rock in Yosemite is granitic. Most people know granite as a hard gray rock with a salt-and-pepper appearance. lndividual grains of light and dark minerals make up the rock, giving it a salt-and-pepper look.

There are many different types of granitic rock in Yosemite, but they all contain two basic light-colored mineral families: feldspars and quartz. They can also have smaller amounts of the darker minerals biotite mica and hornblende.

Yosemite granitic rocks are grouped into different types based on the relative proportion of the minerals found in them and on the size of their mineral crystals. The Geology in Depth section contains more information about different granitic rocks.