Regents Minerals, Igneous & Sedimentary Rocks

Front

What is an extrusive igneous rock?

Back

An extrusive igneous rock is formed from lava that cools and solidifies on the Earth's surface, resulting in a fine-grained texture.

Front

What is rhyolite?

Back

Rhyolite is a light-colored, fine-grained extrusive igneous rock that typically contains quartz and feldspar.

Front

What minerals are commonly found in rhyolite?

Back

Rhyolite commonly contains approximately 40% quartz, 20% potassium feldspar, 20% plagioclase feldspar, and small amounts of biotite mica and hornblende.

Front

What is gabbro?

Back

Gabbro is a dark-colored, coarse-grained intrusive igneous rock that is rich in pyroxene and plagioclase feldspar.

Front

What is the primary difference between extrusive and intrusive igneous rocks?

Back

Extrusive igneous rocks form from lava on the surface, while intrusive igneous rocks form from magma that cools slowly beneath the surface.

Front

What are the commercial sources of iron?

Back

Hematite and magnetite are the two primary commercial sources of iron.

Front

What is pumice rock and how is it formed?

Back

Pumice is a light, porous volcanic rock formed from explosive eruptions of lava that cools rapidly, trapping gas bubbles.

Front

What is the significance of quartz in igneous rocks?

Back

Quartz is a common mineral in igneous rocks, particularly in rhyolite, and contributes to the light color and fine-grained texture.

Front

What is the role of plagioclase feldspar in igneous rocks?

Back

Plagioclase feldspar is a key mineral in both intrusive and extrusive igneous rocks, contributing to their composition and texture.

Front

What is the process of magma cooling?

Back

Magma cooling refers to the process where molten rock cools and solidifies, forming igneous rocks; the rate of cooling affects the rock's texture.