sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, translucent to opaque appearance, conchoidal fracture, and specific gravity of 2.58-2.64.
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 to vitreous luster, translucent to opaque appearance, conchoidal fracture, and specific gravity of 2.58-2.64.
Formation & geological history
Formed by the deposition of silica from groundwater in the cavities of igneous and sedimentary rocks, often developing in concentric bands over millions of years.
Uses & applications
Used extensively in making ornamental items, jewelry, carvings, laboratory mortars and pestles, and as a popular specimen for rock collectors.
Geological facts
Agate is a variety of chalcedony and is often associated with volcanic rocks. Montana, near the geographic coordinates provided, is notably famous for producing the Montana Agate, which often features distinctive reddish-brown dendritic inclusions caused by iron or manganese oxides.
Field identification & locations
Easily identified by its waxy luster, conchoidal fracture, and characteristic banding or translucent layers. Frequently found in river gravels and volcanic regions.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary