"Ward's Phenomena"

Gray and poorly sorted, with a gritty texture.

Coarse grained and abundant in plagioclase feldspar.

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

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

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

Massive, chlorite-rich.

Dark, coarse-grained, and composed chiefly of hornblende.

Shows porphyritic texture in a fine dark matrix abundant large feldspar phenocrysts. Hand specimen.

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

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.