Granite is a type of igneous rock. What determines the size of the crystals that form in a sample of granite?

Question

A.
how many times those minerals have been in granite before
B.
how large the sample is
C.
how quickly the rock cooled
D.
how many impurities are in the granite

Answer 1

The size of the crystals that form in a sample of granite is determined by:

C. how quickly the rock cooled.

Granite forms from the slow cooling of magma beneath the Earth's surface, allowing large crystals to form. If the magma cools quickly, the crystals typically are smaller.