sedimentary
Agate
SiO2 (Chalcedony / Quartz)
AI-generated identification · may be incorrectHardness of 6.5-7 on the Mohs scale, typically exhibits white, gray, brown, and blue banding, waxy to vitreous luster, microcrystalline crystal structure, conchoidal fracture, and specific gravity of 2.6-2.7.
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 6.5-7 on the Mohs scale, typically exhibits white, gray, brown, and blue banding, waxy to vitreous luster, microcrystalline crystal structure, conchoidal fracture, and specific gravity of 2.6-2.7.
Formation & geological history
Formed through the deposition of silica from groundwater in the cavities of ancient volcanic or sedimentary rocks, often developing in concentric layers over millions of years.
Uses & applications
Commonly used in ornamental carvings, jewelry, polished decorative slabs, and as collector specimens.
Geological facts
Agate is one of the most popular stones used in lapidary art and has been prized since ancient times, notably in ancient Greece and Rome for seals, rings, and vessels.
Field identification & locations
Easily identified by its distinctive concentric or parallel banding and waxy luster. Found worldwide, with notable deposits in Brazil, Uruguay, India, Madagascar, and the United States.
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