Which is an example of an igneous rock?

Which is an example of an igneous rock?

Devil’s Tower National Monument in Wyoming is an example of an igneous rock. Rock texture with crystals that are invisible without magnification. type of dark volcanic rock. type of hard, igneous rock. molten rock, or magma, that erupts from volcanoes or fissures in the Earth’s surface.

How did the igneous rock andesite get its name?

Andesite gets its name from the Andes mountains of South America, where arc volcanic rocks mix basaltic magma with granitic crustal rocks, yielding lavas with intermediate compositions. Andesite is less fluid than basalt and erupts with more violence​ because its dissolved gases cannot escape as easily.

Where can I find igneous rocks in the United States?

Volcanic processes has shaped the extrusive igneous rock formations at these parks: Hawai’i Volcanoes National Park, Hawai’i [Geodiversity Atlas] [Park Home] Sunset Crater Volcano National Monument, Arizona [Geodiversity Atlas] [Park Home] Crater Lake National Park, Oregon [Geodiversity Atlas] [Park Home]

Why are igneous rocks called glassy rocks?

They are given this name because the crystals that form within them are so small that they can be seen only with a microscope. If lava cools almost instantly, the rocks that form are glassy with no individual crystals, like obsidian. There are many other kinds of extrusive igneous rocks.

Which igneous rocks have a small grain texture?

Aphanitic (“AY-fa-NIT-ic”) rocks have mineral grains that are mostly too small to be seen with the naked eye or a hand lens, like this rhyolite. Basalt is another igneous rock with the aphanitic texture.

What are igneous rocks used for in iron smelting?

A specimen of gabbro, an igneous mineral that was used as a purifying agent in the iron smelting process at the Saugus Iron Works. This photo shows the ropey texture of a recently crusted pahoehoe flow, as well as its superior strength as a natural insulator.