sedimentary
Tumbled Agate
Silicon dioxide (SiO2)
Hardness of 6.5-7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline crystal structure, translucent to opaque with distinct banding or mottled patterns, specific gravity of 2.58-2.64.
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Physical properties
Hardness of 6.5-7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline crystal structure, translucent to opaque with distinct banding or mottled patterns, specific gravity of 2.58-2.64.
Formation & geological history
Formed by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks over millions of years.
Uses & applications
Commonly used in jewelry, decorative items, ornamental carvings, and as a popular tumbled stone for collectors.
Geological facts
Agates have been used since ancient times (such as by the ancient Greeks and Babylonians) for seals, signet rings, and healing talismans.
Field identification & locations
Can be identified by its conchoidal fracture, waxy luster, and resistance to steel. Found worldwide, often in volcanic rock cavities or riverbeds.
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