How Sand Forms: From Rock Weathering to Sediment Deposition

Sand is granular sediment composed of mineral and rock fragments, typically 0.0625–2 mm in diameter. Its formation is a slow, multi-stage geological process.

1. Parent Rock

Sand originates from pre-existing rocks—granite, sandstone, limestone, shale, etc.

2. Weathering

• Physical: Freeze-thaw, abrasion, thermal expansion.
• Chemical: Dissolution, oxidation, hydrolysis.
• Biological: Root wedging, burrowing organisms.

3. Erosion & Transport

Water, wind, ice, and gravity move fragments, further abrading and rounding them.

4. Deposition

When transport energy drops, sediments settle—in riverbeds, beaches, dunes, deltas.

5. Sorting & Maturation

Hydrodynamic sorting separates grains by size/density. Long transport rounds grains and removes unstable minerals, leaving quartz-rich sand.

Over millions of years, these cycles produce the vast sand deposits found in deserts, beaches, and sandstone formations worldwide.