"gel box"

White and black bands of quartz, feldspar, and biotite; typical foliation.

Red, medium, to coarse-grained iron oxide cement; shows hematite bands.

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.

Gray, fine-grained, massive contact rock.

Fine to medium-grained with biotite.

Gray to buff, with numerous ooliths and fossil fragments.

Gray andesite with phenocrysts of felspar and/or hornblende.

Dense and massive.

Gray, fine to medium-grained “Berea grit”.

Pink and gray bands, with biotite; shows good foliation.

Abundant small black phenocrysts in a gray to brown matrix.

Light gray, fine small clasts.

Red-brown to gray, coarse-grained, containing feldspar and mica.

Samples of Intrusive and Extrusive Igneous Rocks