"Freeze-Dried Specimens"

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, with hornblende as the dominant mafic mineral.

Fine to medium-grained with biotite.

Introduce your students to rocks formed from the cooling of magma and lava.

Includes: six each of obsidian, pumice, and basalt. Set of 18.

Common rocks and minerals for testing and identification studies are 2–3cm each.

Abundant small black phenocrysts in a gray to brown matrix.

Coarse-grained plagioclase and pyroxene with some olivine.

Banded volcanic glass.

Classic, dark; from the Columbia Plateau.

Obsidian is hard black colored, volcanic glass.