sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, microcrystalline crystal structure, opaque to translucent with distinctive banded patterns, specific gravity of 2.58 to 2.64.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, microcrystalline crystal structure, opaque to translucent with distinctive banded patterns, specific gravity of 2.58 to 2.64.
Formation & geological history
Formed primarily within the cavities of volcanic and metamorphic rocks through the deposition of silica-rich groundwater solutions over millions of years.
Uses & applications
Widely used in jewelry, ornamental carvings, polished specimens, decorative objects, and historically for precision instruments like mortar and pestles.
Geological facts
Agate is one of the most popular and varied gemstones known to humankind, named after the Achates River in Sicily where they were first found by ancient Greeks.
Field identification & locations
Easily identified by its characteristic concentric bands and waxy luster; commonly found worldwide in volcanic regions, riverbeds, and gravel deposits.
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