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Lava from Mount Rainier

Part of Hall of Planet Earth.

Lava from Mount Rainier_HERO

These dacite samples from Mount Rainier are 93,500 years old. Their columnlike structure is the result of its rapid cooling against a glacier. Dacite is a characteristic lava of subduction-zone volcanoes, and has a composition between those of basalt and rhyolite, the volcanic equivalent of granite.

Loaned by Mount Rainier National Park