Amazing Agates

Agate: A type of very fine-grained quartz (usually chalcedony) found in various colors that are arranged in bands or in cloudy patterns; used as a gemstone.

Chalcedony is a milky-grayish quartz. The colored bands form when silica-rich water enters empty spaces in the rock. The silica forms crystals. The different colors come from various impurities in the water.

Formula: SiO₂

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