"Freeze-Dried Specimens"

Banded volcanic glass.

Obsidian is hard black colored, volcanic glass.

Classic, very coarse-grained igneous texture.

Medium-grained with biotite.

Light gray, with flow structure.

Coarse, 'salt and pepper': dark pyroxene and light andesine. Provides perfect representation of an intermediate igneous rock.

Dark gray, composed mostly of pyroxene and olivine.

Study the Formation of Different Igneous Rocks

Coarse grained and abundant in plagioclase feldspar.

Gray-to-brown basaltic, with over 50% vesicles.