sedimentary
Agate
Silicon dioxide (Chalcedony), SiO2
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, multicolored with banding patterns, trigonal crystal system, conchoidal fracture, specific gravity of 2.60 to 2.65.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, multicolored with banding patterns, trigonal crystal system, conchoidal fracture, specific gravity of 2.60 to 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
Commonly used in jewelry, decorative ornaments, lapidary arts, and industrial bearings.
Geological facts
Agates are often found in ancient lava flows where silica-rich fluids filled gas bubbles, creating distinct concentric bands.
Field identification & locations
Easily identified by its distinctive multicolored banding and waxy luster, commonly found in river gravels, beaches, and volcanic regions worldwide.
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