sedimentary
Agate Nodule
Silicon Dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, microcrystalline crystal structure, and exhibits conchoidal fracture with no true cleavage.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, microcrystalline crystal structure, and exhibits conchoidal fracture with no true cleavage.
Formation & geological history
Formed through the deposition of silica-rich groundwater solutions within cavities of pre-existing volcanic or sedimentary rocks over millions of years.
Uses & applications
Commonly used in lapidary arts for ornamental carvings, polished display specimens, jewelry, and prized by amateur rockhounds.
Geological facts
Agate banding represents distinct stages of silica deposition in fluid-filled cavities, often trapping water and mineral impurities inside.
Field identification & locations
Identify by its characteristic concentric color bands, smooth weathered outer cortex, and waxy luster on fractured surfaces; found globally in volcanic regions.
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