"pathway PLASTICS, INC."

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

Classic, dark; from the Columbia Plateau.

Light gray, with flow structure.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

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.

Gray andesite with phenocrysts of felspar and/or hornblende.

Abundant small black phenocrysts in a gray to brown matrix.

Samples of Intrusive and Extrusive Igneous Rocks