sedimentary

Agate

Silicon dioxide (SiO2)

Mohs hardness of 6.5-7, exhibiting translucent or opaque banded patterns with waxy luster and microcrystalline quartz structure.

Identified November 14, 2026More sedimentary →

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Physical properties

Mohs hardness of 6.5-7, exhibiting translucent or opaque banded patterns with waxy luster and microcrystalline quartz structure.

Formed through the deposition of silica-rich groundwater in cavities of igneous and sedimentary rocks over millions of years.

Used primarily in ornamental carvings, jewelry, lapidary art, and scientific instruments.

Agate is a variety of chalcedony and often forms within volcanic vesicles, preserving ancient mineral fluid inclusions.

Easily identified by its distinctive concentric banding and conchoidal fracture; commonly found worldwide in volcanic regions.

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

Sandstone or Siltstone

Arenite (if sandstone)

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Shale

Fissile Sedimentary Rock

Sandstone

Arenite

Shale

Clastic sedimentary rock