Which rock type is rich in silica and light-colored minerals?

Which rock type is rich in silica and light-colored minerals?

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

Answer: (B)

Rocks that are rich in silica and light-colored minerals are felsic. Silica-rich minerals like quartz and feldspar give these rocks a light hue, and the high silica content means they crystallize from cooler magmas that produce these light, low-density minerals. This contrasts with mafic rocks, which have more dark ferromagnesian minerals (like pyroxene and olivine) and lower silica, making them darker and denser. Ultramafic rocks are even more dominated by dark minerals and have even less silica, while intermediate rocks sit in between. So the description points to felsic, with common examples including granite and rhyolite.

Rocks that are rich in silica and light-colored minerals are felsic. Silica-rich minerals like quartz and feldspar give these rocks a light hue, and the high silica content means they crystallize from cooler magmas that produce these light, low-density minerals. This contrasts with mafic rocks, which have more dark ferromagnesian minerals (like pyroxene and olivine) and lower silica, making them darker and denser. Ultramafic rocks are even more dominated by dark minerals and have even less silica, while intermediate rocks sit in between. So the description points to felsic, with common examples including granite and rhyolite.