| Igneous Rocks | Types of Igneous Rocks | Volcanic Ash | Basalt | Andesite | Dacite | Ryholite |

Flow banding in rhyolite lava from Mono-Inyo Craters volcanic chain, California (black bands composed of obsidian)

Rhyolite is a light-colored rock with silica (SiO2) content greater than about 68 weight percent. Sodium and potassium oxides both can reach about 5 weight percent. Common mineral types include quartz, feldspar and biotite and are often found in a glassy matrix. Rhyolite is erupted at temperatures of 700 to 850° C.

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