sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture with no true cleavage, and specific gravity around 2.60-2.65.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture with no true cleavage, and specific gravity around 2.60-2.65.
Formation & geological history
Formed mainly in cavities of volcanic and metamorphic rocks through the deposition of silica from groundwater solutions over millions of years.
Uses & applications
Used widely in ornamental objects, jewelry, polished specimens, decorative carvings, and precision instruments.
Geological facts
Agate is one of the most popular lapidary stones, known for its intricate banded patterns formed by successive layers of solutions filling cavities.
Field identification & locations
Found worldwide in volcanic regions, riverbeds, and beaches. Easily identified by its waxy luster, hardness, and distinct translucent banding.
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