sedimentary
Agate Geode
Silicon dioxide (Chalcedony/Quartz), SiO2
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture, and colors ranging from brown to blue-grey.
Identified More sedimentary →
Explore Agate Geode in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture, and colors ranging from brown to blue-grey.
Formation & geological history
Formed through the deposition of silica-rich groundwater within cavities of volcanic or sedimentary rocks over millions of years.
Uses & applications
Widely used in ornamental carvings, jewelry, lapidary arts, and as popular specimens for mineral collectors.
Geological facts
Geodes form when dissolved minerals slowly precipitate along the inside walls of hollow cavities, often leaving quartz crystal centers.
Field identification & locations
Easily identified by concentric color banding and a hollow center lined with microcrystalline quartz; found globally, notably in Brazil and Mexico.
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