Q:

How are granite and rhyolite different?

A:

Rhyolite differs from granite in that it is formed via volcanism, has a greater abundance of potassium versus sodium, does not contain much if any muscovite and tends to cool much more quickly, resulting in glassy or microcrystalline structures. Otherwise, granite and rhyolite have very similar chemical compositions, and some rhyolite is difficult to distinguish from granite. Other types of rhyolite, such as obsidian or pumice, are easy to distinguish.

Rhyolite is very diverse in its appearance despite its typical chemical composition due to the varied circumstances of solidification. Granite, on the other hand, while varied in color and coarseness of grain, is much more uniform and identifiable. Unlike rhyolite, which solidifies within or outside volcanoes, granite solidifies from magma deep beneath the earth. Its slow solidification allows it to form large, granular mineral crystals. Rhyolite usually cools quickly, creating only small crystals or even uncrystallized glasses. Glasses are amorphous solids, with constituent molecules frozen in a relatively random configuration. Perlite is a form of glassy rhyolite similar to obsidian, but with a much higher water content. Pumice is yet another form of rhyolite volcanic glass. Rhyolite cools extremely rapidly, releasing all contained gases, thus creating a porous, froth-like glass.

Learn More

Related Questions

  • Q:

    What are granite and gabbro?

    A:

    Granite and gabbro are igneous rocks formed through the cooling and crystallization of magma in the Earth's crust. They are identified by their specific mineral content and composition.

    Full Answer >
    Filed Under:
  • Q:

    How is granite formed?

    A:

    Granite is an igneous rock that forms when a pocket of magma rises into the upper levels of the Earth's crust and slowly cools. Cooling slowly gives granite, which is composed mainly of feldspar and quartz, enough time to develop large crystals that make the stone very hard and strong. Some granite, known as gneiss, can form from sedimentary rock that has gone through a long metamorphosis.

    Full Answer >
    Filed Under:
  • Q:

    What are all of the uses for granite?

    A:

    Granite is one of the strongest, most attractive rocks naturally produced, which makes it valuable to builders and homeowners for a number of interior and exterior applications. Granite is used in projects to provide elegance and quality.

    Full Answer >
    Filed Under:
  • Q:

    How does granite form?

    A:

    As of 2014, geologists contend that granite is a plutonic rock resulting from deeply buried shale and sandstone that melted, partially melted or metamorphosed, depending on the category of granite in question. Igneous granite forcefully ripped through the Earth's crust, while metamorphic has no evidence of fluidity.

    Full Answer >
    Filed Under:

Explore