"physics kits"

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

Shiny black volcanic glass showing conchoidal fracture and some spherulites.

Porphyritic igneous rock containing biotite, feldspar, and hornblende.

Gabbro is Mafic igneous rock formed deep underground consisting of olivine and pyroxene.

Introduce your students to rocks formed from the cooling of magma and lava.