sedimentary
Agate
Silicon Dioxide (SiO2)
Hardness of 6.5 to 7 on the Mohs scale, typically translucent to opaque with a waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture, and no true cleavage.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, typically translucent to opaque with a waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture, and no true cleavage.
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 for ornamental objects, jewelry, gemstone carvings, and precision instruments due to its durability.
Geological facts
Agate was highly valued as a talisman in ancient civilizations and is named after the Achates River in Sicily where stones were first found in antiquity.
Field identification & locations
Identified by its distinctive concentric banding and waxy luster; commonly found worldwide in volcanic regions, river gravels, and ancient lava flows.
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