sedimentary
Grey River Pebble (Likely Quartz-rich or Limestone)
Clastic Sedimentary Rock (typically SiO2 or CaCO3 based)
Hardness: 3-7 (Mohs scale), Color: light grey to whitish, Luster: dull to matte, Crystal structure: microcrystalline/aphanitic, Cleavage: none, Specific gravity: 2.5-2.7
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Physical properties
Hardness: 3-7 (Mohs scale), Color: light grey to whitish, Luster: dull to matte, Crystal structure: microcrystalline/aphanitic, Cleavage: none, Specific gravity: 2.5-2.7
Formation & geological history
Formed through the mechanical weathering and erosion of larger rock formations, transported by water systems (rivers/streams). Geological age varies widely from Paleozoic to Cenozoic depending on the source outcrop.
Uses & applications
Used primarily as decorative landscaping stone, drainage material in construction, or for educational rock painting. Polished versions are used in aquariums.
Geological facts
River pebbles become smooth through a process called abrasion, effectively acting as a natural 'rock tumbler' over hundreds or thousands of years. They often represent the most durable remnants of a region's local geology.
Field identification & locations
Identify by its rounded, smooth 'water-worn' texture and lack of sharp edges. Found worldwide in stream beds, beaches, and glacial deposits. For collectors, look for unique inclusions or translucency.
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