sedimentary
Agate
Silicon dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy luster, microcrystalline quartz structure, and translucent appearance with varied banding colors.
Identified More sedimentary →
Explore Agate in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy luster, microcrystalline quartz structure, and translucent appearance with varied banding colors.
Formation & geological history
Forms by the deposition of silica from groundwater in cavities of igneous and sedimentary rocks, often over millions of years.
Uses & applications
Used widely in ornamental jewelry, decorative carvings, and precision instruments like mortar and pestles.
Geological facts
Agate banding reflects successive layers of silica deposition inside volcanic vesicles or ancient rock cavities.
Field identification & locations
Identified by conchoidal fracture, distinct concentric color bands, and a waxy luster; commonly found worldwide in volcanic rock deposits.
More like this
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