Light coloured aphanitic rocks ________.
A)always form deep in the crust
B)consist predominantly of small non-ferromagnesian minerals
C)never form at the surface of the Earth
D)consist predominantly of large ferromagnesian minerals

Question

Quizplus · Accepted Answer

Aphanitic rocks have small mineral crystals that are not visible to the naked eye. Light coloured aphanitic rocks consist predominantly of small non-ferromagnesian minerals, such as feldspar and quartz, which are typically found in igneous rocks that form at or near the surface of the Earth. They can also form deep in the crust, but this is not always the case. Therefore, options A and C are incorrect. Option D is also incorrect, as ferromagnesian minerals, such as pyroxene and amphibole, are typically dark in colour.

Light Coloured Aphanitic Rocks ________