Question

Which describes pumice and obsidian? A. Both pumice and obsidian are coarse-grained intrusive igneous rocks. B. Pumice is a coarse-grained extrusive igneous rock, while obsidian is a fine-grained intrusive igneous rock. C. Pumice is a fine-grained intrusive igneous rock, while obsidian is a coarse-grained extrusive igneous rock. D. Both pumice and obsidian are fine-grained extrusive igneous rocks.

Answer 1

Pumice and obsidian are types of extrusive igneous rocks that lack crystals and minerals. Pumice has a frothy texture due to the presence of gas bubbles, while obsidian is glassy-textured. Both rocks formed from lava that cooled on the surface of the Earth.

Step-by-step explanation:

Pumice is a distinctively frothy-textured, felsic, extrusive igneous rock. It is lightweight, typically whitish or light grayish in color, and has a frothy texture due to the presence of many gas bubbles. Pumice is a volcanic glass, lacking crystals and minerals.

Obsidian, on the other hand, is a glassy-textured, felsic, extrusive igneous rock. It is typically black in color but can also be felsic obsidian or mafic obsidian. Like pumice, obsidian lacks crystals and minerals.

Both pumice and obsidian belong to the category of extrusive igneous rocks, which means they formed from lava that cooled on the surface of the Earth.

Answer 2

the answer is C.)Pumice is a fine-grained intrusive igneous rock, while obsidian is a coarse-grained extrusive igneous rock