sedimentary
Agate
Silicon dioxide, SiO2 (Chalcedony variety)
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy luster, conchoidal fracture, and microscopic fibrous quartz structure showing banded colors.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy luster, conchoidal fracture, and microscopic fibrous quartz structure showing banded colors.
Formation & geological history
Forms by the deposition of silica from groundwater in cavities of igneous and sedimentary rocks, typically over millions of years.
Uses & applications
Widely used in lapidary arts, ornamental carvings, jewelry, and precision instruments due to its durability.
Geological facts
Agate was named by Theophrastus after the Achates River in Sicily where specimens were found in antiquity.
Field identification & locations
Identified by waxy luster and distinctive concentric bands; commonly found globally in volcanic rock cavities and stream gravels.
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Sandstone or Siltstone
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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