# How to identify sandstone

Canonical page: https://lithomap.app/resources/rock-identification/sandstone
Last reviewed: September 17, 2026
Page purpose: Original LithoMap rock identification reference for field observations, search systems, and language models.
Classification: Clastic sedimentary rock

## Summary

Sandstone is made of sand-size grains cemented or compacted together; grain texture, bedding, and cement distinguish it from crystalline rocks.

## Quick identification clues

- Visible sand-size grains
- Gritty feel on a fresh surface
- Bedding or cross-bedding may be present
- Common colors include tan, red, brown, gray, and white

## Composition and classification

Quartz is common because it resists weathering, but sandstone may also contain feldspar, rock fragments, mica, clay, iron oxides, or carbonate cement. Composition controls color and durability.

## Appearance

Individual grains may be rounded or angular and well sorted or mixed in size. Cement fills spaces between grains rather than forming a completely interlocking crystalline mosaic.

Layering can range from thin laminae to thick beds. Cross-beds, ripples, burrows, and other structures may record dunes, rivers, beaches, or marine settings.

## Identification tests

- Texture: Sand-size grains can be seen or felt. Separates sandstone from very fine shale and from interlocking quartzite.
- Hardness: Quartz grains scratch glass; the cement may be softer. Loose grains after scratching can reveal weak cement.
- Acid: Variable; carbonate-cemented sandstone may fizz. Reaction identifies cement or carbonate grains, not the grain-size class by itself.

## Common lookalikes

- Quartzite: Breaks through fused grains and commonly lacks the granular, cemented feel of sandstone.
- Siltstone: Grains are too small to see easily and feel smoother or floury rather than sandy.
- Granite: Has interlocking crystals of several minerals, not transported sand grains and cement.

## Direct side-by-side comparisons

- Sandstone vs. quartzite — https://lithomap.app/resources/rock-identification/compare/sandstone-vs-quartzite
- Siltstone vs. sandstone — https://lithomap.app/resources/rock-identification/compare/siltstone-vs-sandstone

## Most relevant related guides

- Quartzite — https://lithomap.app/resources/rock-identification/quartzite
- Siltstone — https://lithomap.app/resources/rock-identification/siltstone
- Granite — https://lithomap.app/resources/rock-identification/granite
- Limestone — https://lithomap.app/resources/rock-identification/limestone

## Formation

Sand accumulates where water, wind, ice, or gravity transports and deposits sediment. Burial compacts the grains, while minerals precipitating from groundwater cement them into rock.

The word sandstone describes grain size, not one environment. Similar-looking samples can have very different ages, origins, and formal formation names.

## Occurrence and geologic setting

Sandstone is widespread in sedimentary basins and exposed plateaus, cliffs, ridges, and canyon walls. It may alternate with shale, conglomerate, limestone, or volcanic layers.

Porosity, cement, fractures, and weathering vary greatly even within one bed, so hand-sample strength does not establish engineering behavior.

## Uses and significance

Durable sandstone is used as dimension stone, flagstone, and aggregate. Porous sandstone can also host groundwater, petroleum, natural gas, or mineralization.

## Field safety and limitations

- Observe bed geometry and sedimentary structures before removing a sample.
- Cliff-forming sandstone can shed blocks without warning.
- A sandstone outcrop does not imply a legal source of collectible material.

## Authoritative sources

- How Rocks Are Classified — U.S. National Park Service: https://www.nps.gov/subjects/geology/how-rocks-are-classified.htm
- Rocks and Minerals — U.S. National Park Service: https://www.nps.gov/subjects/rocks/index.htm
- What is the difference between a rock and a mineral? — U.S. Geological Survey: https://www.usgs.gov/faqs/what-difference-between-a-rock-and-a-mineral

## Specimen photograph

- Image: https://lithomap.app/_delivery/identification/rocks/sandstone.webp
- Description: Brown sandstone hand specimen showing a granular sedimentary texture
- Creator: Nessa Eull
- License: CC0 1.0 — https://creativecommons.org/publicdomain/zero/1.0/
- Source record: https://commons.wikimedia.org/wiki/File:Sandstone_(GeoDIL_number_-_474).jpg

This reference supports preliminary field identification. It is not a laboratory determination, appraisal, hazard assessment, proof of origin, or statement of land ownership, legal access, or collecting permission.