Obsidian is a glassy black igneous rock. A sample of obsidian is shown.

Question

Which type of rock forms in a similar manner as obsidian but at a slower rate?
M. schist, which forms under extreme heat and pressure
P. conglomerate, which forms when different-sized sediments cement together
R. gypsum, which forms when water evaporates and leaves behind minerals
S. granite, which forms as magma cools deep underground

Answer 1

S. granite, which forms as magma cools deep underground.