sedimentary
Agate
Silicon dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, typically brown, red, grey, or banded colors, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture with no cleavage, specific gravity of 2.6 to 2.65.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, typically brown, red, grey, or banded colors, waxy to vitreous luster, cryptocrystalline crystal structure, conchoidal fracture with no cleavage, specific gravity of 2.6 to 2.65.
Formation & geological history
Forms primarily within cavities of volcanic and metamorphic rocks through the deposition of silica-rich groundwater solutions over millions of years.
Uses & applications
Used in jewelry, ornamental carvings, decorative items, and historically for precision instruments and mortars/pestles.
Geological facts
Agate is one of the most popular and varied forms of chalcedony, named after the Achates River in Sicily where they were found in ancient times.
Field identification & locations
Identified by its waxy luster, conchoidal fracture, and sometimes translucent banding. Commonly found in regions with past volcanic activity worldwide.
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