Specimens

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Banded volcanic glass.

Glassy; most specimens float in water.

Light gray, with flow structure.

Gray andesite with phenocrysts of felspar and/or hornblende.

Classic, dark; from the Columbia Plateau.

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

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

Coarse grained and abundant in plagioclase feldspar.

Volcanic glass with snowflakes embedded throughout.

Pegmatite is igneous rock similar to granite but with larger crystals.

Obsidian is hard black colored, volcanic glass.