Size
Sand particles range from 0.0625 to 2 millimeters. Boulders range from 256 millimeters to several meters.
Composition
Sand consists of tiny rock and mineral particles like quartz, feldspar, and mica. Boulders are solid pieces of rock from igneous, sedimentary, or metamorphic formations.
Formation Process
Sand forms through weathering and erosion, then deposits in low-energy areas like beaches and riverbeds. Boulders form through weathering, erosion, and tectonic activity, including glacial transport and rockfalls.
Location
Sand is found in beaches, deserts, riverbeds, and sandstone formations. Boulders occur in mountainous regions, riverbeds, glacial deposits, hillsides, and coastlines.
Summary
Sand and boulders differ greatly in size, composition, formation, and distribution, but both are essential to Earth's ecosystems.