sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically exhibits distinct banded patterns or concentric rings formed in cavities.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically exhibits distinct banded patterns or concentric rings formed in cavities.
Formation & geological history
Formed through the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, often over millions of years.
Uses & applications
Commonly used in jewelry, ornamental carvings, polished display specimens, and industrial knife-edge bearings due to its durability.
Geological facts
Agates were highly prized in the ancient world for use in signet rings and ornamental vessels, and they are frequently found in volcanic regions and riverbeds worldwide.
Field identification & locations
Can be identified in the field by its waxy luster, concentric banding or colorful translucency, and hardness that easily scratches glass.
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