"gel box"

Earthy, porous calcareous tufa.

Hematite-cemented quartz; orthoquartzite.

Chlorite-bearing.

Fine crystalline, pure calcite.

A comprehensive classroom survey set of minerals and rocks.

Classic, very coarse-grained igneous texture.

Represents a Wide Range of Depositional Environments and Rock Textures

Dark gray, composed mostly of pyroxene and olivine.

Dark-green 'verde antique', containing some chlorite and calcite.

Brownish black, intermediate stage between peat and bituminous coal.

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

Lustrous, black 'hard coal'.

Small, rounded pebbles and tightly cemented granules.

Slaty cleavage; contains hematite.

White, mature, friable.

Buff, coarse, crystalline “Austin Marble” with shell casts and molds.