sedimentary
Agate
Silicon dioxide (chalcedony, SiO2)
AI-generated identification · may be incorrectMohs hardness of 6.5-7. Color ranges from brown to translucent gray with concentric banding. Luster is waxy to vitreous with a cryptocrystalline crystal structure.
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Physical properties
Mohs hardness of 6.5-7. Color ranges from brown to translucent gray with concentric banding. Luster is waxy to vitreous with a cryptocrystalline crystal structure.
Formation & geological history
Forms in cavities of volcanic and metamorphic rocks through the deposition of silica-rich groundwater over millions of years.
Uses & applications
Used extensively in jewelry, ornamental carvings, decorative items, and precision scientific instruments.
Geological facts
Agate is one of the most popular stones used in lapidary art. Ancient civilizations valued it for protective talismans and healing amulets.
Field identification & locations
Identify by its distinct concentric color bands, waxy luster, and conchoidal fracture. Found worldwide, particularly in Brazil, India, and the western United States.
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