Class: Igneous

Subclass: Plutonic(intrusive)

Rock: Granite

General Characteristics: Coarse-grained:"salt & pepper: appearance: from high-silica felsic magma; plutonic equivalent of rhyolite.

Rock: Diorite

General Characteristics: Coarse-grained; from intermediate silica magma; plutonic equivalent of andesite

Rock: Gabbro

General Characteristics: Coarse-grained; black or dark gray color; from low-silica mafic magma; plutonic equivlent of andesite

Rock: Peridotite

General Characteristics: Common mantle rock consisting primarily of olivine and/or pyroxene

Subclass: Volcanic(extrusive)

Rock: Rhyolite

General Characteristics: Light color; from high-silica felsic magma; volcanic equivalent of granite

Rock: Andesite

General Characteristics: Typically gray in color; from high-silica felsic magma; volcanic equivalent of granite

Rock: Basalt

General Characteristics: Usually black in color; from low-silica mafic magma; volcanic equivalent of granite

Rock: Obsidian

General Characteristics: Volcanic glass; typically black in color and rhyolitic in composition

Rock: Pumice

General Characteristics: Volcanic glass with frothy texture; often rhyolitic in composition

Rock: Tuff

General Characteristics: Rock made from volcanic ash or pyroclastic flow deposits