"gel box"

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

Brownish gray, kerogen-rich; commercial oil source.

Light gray, with flow structure.

Silvery, paragranite and muscovite-rich with medium garnet crystals.

Fine, common limestone; massive, and will fizzle with HCl.

Small, rounded pebbles and tightly cemented granules.

Grayish black trap rock.

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

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

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