sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, and displays characteristic concentric banding in various colors.
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Physical properties
Hardness of 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, and displays characteristic concentric banding in various colors.
Formation & geological history
Forms by the deposition of silica from groundwater in cavities of igneous and sedimentary rocks over millions of years.
Uses & applications
Used primarily in jewelry, ornamental carvings, and precision instruments like mortars and pestles.
Geological facts
Agate is a variety of chalcedony and was named by the Greek philosopher Theophrastus after the Achates River in Sicily.
Field identification & locations
Identified by its waxy luster, conchoidal fracture, and distinct color bands; commonly found worldwide in volcanic rock cavities.
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Sandstone or Siltstone
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