Rock Specimens

Study the Formation of Different Igneous Rocks

Glassy; most specimens float in water.

Grayish black trap rock.

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

Dark gray with abundant gas pocket vesicles.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Volcanic glass with snowflakes embedded throughout.

Gray, fine, friable, with abundant small sanidine crystal fragments.

Classic, dark; from the Columbia Plateau.

Light gray, with flow structure.