"gel box"

Classic, dark; from the Columbia Plateau.

Medium-grained with biotite.

Light gray, earthy.

Chlorite-mica with perfect slaty cleavage.

Brownish gray, kerogen-rich; commercial oil source.

Pink/gray coarse carbonate rock.

Coarse-grained, with microcline, biotite and horblende phenocrysts.

Light gray, fine-grained, well-foliated, schistose.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

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

Buff-colored, coarse, detrital limestone, with cemented shell fragments.

Well-cemented, medium-grained orthoquartzite.

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

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

Dark gray, with hornblende as the dominant mafic mineral.

Light gray, with flow structure.