Which type of igneous rock has a high silica content?

Which type of igneous rock has a high silica content?

• A. Mafic
• B. Ultramafic
• C. Intermediate
• D. Felsic

Answer: (D)

Felsic rocks are the silica-rich end of igneous rocks. They are made mainly of light-colored, silica-rich minerals such as quartz and feldspar, which gives them the highest SiO2 content among the main igneous groups. Because of these minerals, felsic rocks stand out as having more silica than ultramafic (rich in magnesium and iron with little silica), mafic (more Mg and Fe with moderately lower silica), and intermediate rocks (between felsic and mafic). The high silica content also makes felsic magmas more viscous, influencing how they erupt and crystallize, and explains why granitic rocks like granite and rhyolite are felsic.

Felsic rocks are the silica-rich end of igneous rocks. They are made mainly of light-colored, silica-rich minerals such as quartz and feldspar, which gives them the highest SiO2 content among the main igneous groups. Because of these minerals, felsic rocks stand out as having more silica than ultramafic (rich in magnesium and iron with little silica), mafic (more Mg and Fe with moderately lower silica), and intermediate rocks (between felsic and mafic). The high silica content also makes felsic magmas more viscous, influencing how they erupt and crystallize, and explains why granitic rocks like granite and rhyolite are felsic.