River Pebbles and Quartz

Physical Properties

Hardness: 6-7 on Mohs scale; Color: variety of whites, browns, grays, and pinks; Luster: vitreous to dull/earthy; Crystal Structure: mainly cryptocrystalline or coarse-grained; Cleavage: none/conchoidal.

Formation & Geological History

Formed through various geological processes including cooling of magma (granite), metamorphism (quartzite), and mechanical erosion in riverbeds or coastal environments over millions of years.

Uses & Applications

Used in landscaping, decorative aquariums, craft jewelry, construction aggregates, and as starter pieces for rock tumbling and amateur collections.

Geological Facts

River pebbles become smooth through a process called saltation, where they are bounced along a riverbed, grinding against other rocks to remove sharp edges.

Field Identification & Locations

Identify in the field by looking for rounded, smooth surfaces near water sources or glacial deposits. Common in all geographical regions with fluvial history.

Identified on: 4/21/2026

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