Common Igneous Rocks (Part 4)
Rhyolite
Rhyolite is an aphanitic, felsic igneous rock composed primarily of orthoclase feldspar and quartz. A few larger crystals of orthoclase feldspar are visible in this sample.
Rhyolite (Photograph by Parvinder Sethi)
Basalt
Basalt is an aphanitic, mafic igneous rock. Its dark color is due to its dark-colored mineral composition.
Basalt (Photograph by Parvinder Sethi)