A dark colored igneous rock with no visible crystals cooled ____.
A) slowly in a magma chamber
B) quickly in a magma chamber
C) slowly on the Earth's surface
D) quickly on the Earth's surface
E) none of these

Question

Quizplus · Accepted Answer

A dark colored igneous rock with no visible crystals cooled quickly on the Earth's surface. This is because when magma cools quickly on the surface, there is not enough time for large crystals to form. As a result, the rock appears dark and fine-grained. Slow cooling in a magma chamber would allow for the formation of larger crystals, while slow cooling on the Earth's surface would result in weathering and erosion before the rock had a chance to solidify.

A Dark Colored Igneous Rock with No Visible Crystals Cooled