"Freeze-Dried Specimens"

Gray andesite with phenocrysts of felspar and/or hornblende.

Porphyritic igneous rock containing biotite, feldspar, and hornblende.

Pegmatite is igneous rock similar to granite but with larger crystals.

Sale

Pumice is light colored glassy rock that floats in water.

Dark gray, with hornblende as the dominant mafic mineral.

Fine to medium-grained with biotite.

Dark gray, composed mostly of pyroxene and olivine.

Study the Formation of Different Igneous Rocks

Coarse grained and abundant in plagioclase feldspar.

Classic, very coarse-grained igneous texture.