"gel box"

Study the Formation of Different Igneous Rocks

Medium-grained with biotite.

Classic, dark; from the Columbia Plateau.

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

Light gray, with flow structure.

Grayish black trap rock.

Dark gray with abundant gas pocket vesicles.

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

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.

Samples of Intrusive and Extrusive Igneous Rocks

Classic, very coarse-grained igneous texture.

Dark gray, composed mostly of pyroxene and olivine.

Coarse-grained plagioclase and pyroxene with some olivine.

Gray-to-brown basaltic, with over 50% vesicles.