sedimentary
Agate
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, banded color patterns ranging from white and brown to blue and red, with a cryptocrystalline structure.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, banded color patterns ranging from white and brown to blue and red, with a cryptocrystalline structure.
Formation & geological history
Formed by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, often developing over millions of years.
Uses & applications
Widely used in ornamental carvings, jewelry, polished display specimens, and industrial precision instruments due to its durability.
Geological facts
Agate is a variety of chalcedony that typically forms in concentric layers inside ancient volcanic vesicles. It was named by Theophrastus after the Achates River in Sicily.
Field identification & locations
Identify in the field by its distinct concentric color banding and waxy fracture surfaces. Commonly found worldwide, notably in Brazil, Uruguay, and the United States.
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Other sedimentary specimens
Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion
Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image
fossil
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary