sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, concoidal fracture, specific gravity of 2.60 to 2.65, often shows concentric banding in various colors.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, concoidal fracture, specific gravity of 2.60 to 2.65, often shows concentric banding in various colors.
Formation & geological history
Formed mainly in cavities of volcanic rocks or ancient lavas through the slow deposition of silica-rich groundwater over millions of years.
Uses & applications
Used in jewelry, ornamental carvings, polished display specimens, mortar and pestle sets, and historical precision instruments.
Geological facts
Agate was highly prized in ancient civilizations like Ancient Greece and Egypt for signet rings and amulets, named after the Achates River in Sicily.
Field identification & locations
Easily identified by its distinctive waxy luster and curved banding; frequently found in regions with volcanic activity worldwide.
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