"Avantor"

Exemplary display of hexoctahedral crystal shape.

Light gray, fine small clasts.

Brownish black, intermediate stage between peat and bituminous coal.

Classic, very coarse-grained igneous texture.

Gray, fine-grained, massive contact rock.

Fine crystalline, pure calcite.

Compact Plant Fiber Masses.

Dark gray, composed mostly of pyroxene and olivine.

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

Gray to brown mudstone with abundant silt.

Gray and poorly sorted, with a gritty texture.

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

Black, fissile; commonly with carbonized fossil plant impressions.

Survey set improves student's recognition of all three major rock groups.

Feldspar group; calcium end member plagioclase crystals in pyroxene matrix.

When minerals, rocks, and fossils cannot be accurately identified by macroscopic observation and testing, thin section slides can reveal the composition and structure of the specimens on a microscopic level.