Question

A sample of basalt has smaller crystals than a sample of granite. What is the most likely reason for this? The basalt

a.forms when magma cools slowly.
b.forms when magma cools quickly.
c.contains lighter elements than granite.
d.contains heavier elements than granite.

Answer 1

b. forms when magma cools quickly. The crystals in the basalt sample are smaller because the molten lava has cooled down quickly and the crystals didn't have time to grow. Granite, on the other hand, is a rock which has cooled slowly, thus the crystals are larger.