sedimentary

Siltstone (Yellow/Brown Sandstone or Siltstone)

Siltstone / Fine-grained Sandstone (rich in iron oxides like limonite)

Hardness: 6-7 on the Mohs scale depending on cementation; Color: Mustard brown to yellowish-tan; Luster: Dull, earthy; Crystal Structure: Microcrystalline to fine-grained particulate matrix; Cleavage: None, exhibits blocky to uneven fracture; Specific Gravity: 2.2-2.8.

Hardness: 6-7 on the Mohs scale depending on cementation
Color: Mustard brown to yellowish-tan
Luster: Dull, earthy

Identified July 22, 2026More sedimentary →

Explore Siltstone (Yellow/Brown Sandstone or Siltstone) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from the compaction and cementation of fine silty and sandy sediments deposited in river, lake, or shallow marine environments. The yellowish-brown coloration comes from iron oxide (limonite) mineral staining during diagenesis.

Uses & applications

Used primarily in building construction, paving stones, landscaping, aggregate materials, and as educational rock specimens.

Geological facts

Yellow siltstones and sandstones often feature detailed bedding structures and can sometimes host microfossils or plant impressions. The iron oxides coating the grains act as both a natural pigment and a cementing agent.

Field identification & locations

Identified in the field by its gritty or slightly powdery texture, earthy brown-yellow uniform color, and fine-grained matrix. Found abundantly in sedimentary basins worldwide.

Other sedimentary specimens

See all

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Sedimentary Sandstone

Arenite (Sedimentary Rock)

sedimentary

Fossiliferous Concretion

Septarian Concretion containing Brachiopods/Crinoids

fossil

Shale

Shale (clastic sedimentary rock)

sedimentary

Brown Sandstone (River Rock)

Arenite

sedimentary

Shale

Argillaceous sedimentary rock

sedimentary