Igneous rocks that cool more quickly have smaller mineral crystals, while igneous rocks that cool more slowly have larger mineral crystals. how would a rock that formed from lava cooling on the earth's surface compare with a rock that formed from magma cooling deep in the earth's crust? a. the rock that formed from lava would have larger crystals than the rock that formed from magma. b. crystal size would be very small and identical in both rocks. c. crystal size would be very large and identical in both rocks. d. the rock that formed from lava would have smaller crystals than the rock that formed from magma.