sedimentary
Agate
Silicon dioxide (chalcedony, SiO2)
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically exhibits banded or layered colors.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically exhibits banded or layered colors.
Formation & geological history
Forms by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, often over millions of years.
Uses & applications
Used extensively for ornamental objects, jewelry, decorative carvings, and precision instruments like mortars and pestles.
Geological facts
Agate was highly prized in the ancient world for seal rings and talismans, with famous historical workshops in Nahe, Germany.
Field identification & locations
Identify in the field by its distinct concentric color bands, smooth waxy feel, and translucent edges; commonly found in riverbeds and volcanic regions worldwide.
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