"Avantor"

Study the Formation of Different Igneous Rocks

Coarse-grained plagioclase and pyroxene with some olivine.

Dark gray, with hornblende as the dominant mafic mineral.

Fine to medium-grained with biotite.

Medium-grained with biotite.

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

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Glassy; most specimens float in water.

Light gray, with flow structure.

Gray andesite with phenocrysts of felspar and/or hornblende.