GABBRO BASALT

DIORITE ANDESITE (PORPHYRY)

GRANITE RHYOLITE PUMICE OBSIDIAN

Cooling History/TextureSlow Cooling

and Coarse GrainedFast Cooling

and Fine GrainedVery Fast Cooling

and Glassy/Cellular

Maf

ic a

ndD

ark

Col

orFe

lsic

and

Ligh

t Col

orIn

term

ed. an

dIn

term

ed. C

olor

SCORIA

L.S. Fichtergeollab.jmu.edu/Fichter/IgnRx/introigrx.html

A CLASSIFICATION OF IGNEOUS ROCKS