"Ward's Phenomena Lab Activities"

Grayish black trap rock.

Dark gray, with hornblende as the dominant mafic mineral.

Fine to medium-grained with biotite.

Gray andesite with phenocrysts of felspar and/or hornblende.

Abundant small black phenocrysts in a gray to brown matrix.

Classic, dark; from the Columbia Plateau.

Medium-grained with biotite.

Light gray, with flow structure.

Dark gray, composed mostly of pyroxene and olivine.

Samples of Intrusive and Extrusive Igneous Rocks