sedimentary
Agate
Silicon dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy luster, microcrystalline quartz structure, conchoidal fracture, and variable translucent banding colors.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy luster, microcrystalline quartz structure, conchoidal fracture, and variable translucent banding colors.
Formation & geological history
Forms by the deposition of silica from groundwater in cavities of igneous or sedimentary rocks, often over millions of years.
Uses & applications
Used widely in jewelry, decorative ornaments, carving, and industrial knife-edge bearings due to its durability.
Geological facts
Agate is often associated with volcanic rocks where ancient gas bubbles became filled with silica-rich fluids layer by layer.
Field identification & locations
Identify by its distinct waxy luster, conchoidal fracture, and concentric banding. Commonly found in riverbeds, volcanic regions, and gravel deposits worldwide.
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Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
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