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 Rhyolite
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Vesicular Rhyolite
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Rhyolite & Vesicular Rhyolite:
Rhyolite is an extrusive igneous rock. That is, it forms at or very near the surface of the earth. Magma on the surface cools very rapidly giving the minerals in the rock little time to form crystals. That's why rhyolite has a fine texture, crystals less than 1mm in diameter.
Vesicular rhyolite is formed from the same minerals however it contains vessicles, small bubbles or gas pockets. Vessicles form when gases dissolved in the magma escape.
Both rocks are FELSIC, light in color and low density.
Notice that vesicular rhyolite, rhyolite, granite, and pegmatite are all formed from the same minerals (pink zone).
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Rhyolite
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Vesicular Rhyolite
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