"PARKWAY PLASTICS, INC."

Hooked Mass Sets provide accurate results.

Measure the current in DC circuits.

Measure the potential difference in DC circuits.

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

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

Typical green-gray, fissile, clay-rich.

Gray to brown mudstone with abundant silt.

Dark gray, with hornblende as the dominant mafic mineral.

Himalayan mineral great for teaching and display.

Neatly packaged for convenient study.

Coarse-grained plagioclase and pyroxene with some olivine.

Ideal for sampling ponds and lakes.

Light gray, with flow structure.

Slaty cleavage; contains hematite.

White, mature, friable.

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