sedimentary
Agate
Silicon dioxide (chalcedony), SiO2
AI-generated identification · may be incorrectMohs hardness of 6.5 to 7; displays varied red, brown, and white concentric banding; waxy to vitreous luster; microcrystalline crystal structure.
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Physical properties
Mohs hardness of 6.5 to 7; displays varied red, brown, and white concentric banding; waxy to vitreous luster; microcrystalline crystal structure.
Formation & geological history
Formed by the deposition of silica from groundwater in cavities of igneous and sedimentary rocks over millions of years.
Uses & applications
Widely used in ornamental jewelry, decorative carvings, and precision instruments.
Geological facts
Agate bands represent successive layers of fluid deposition within volcanic cavities, creating unique patterns.
Field identification & locations
Identify by its waxy luster, hardness exceeding steel, and distinct curved banding; found globally in volcanic regions.
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Sandstone or Siltstone
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