Quartz Pebble
Silicon Dioxide (SiO2)
Rock Type: sedimentary

Physical Properties
Hardness: 7 on Mohs scale; Color: tan to off-white; Luster: vitreous or dull (weathered); Crystal structure: Trigonal (often hidden in pebbles); Specific gravity: 2.65
Formation & Geological History
Formed through the weathering and erosion of larger igneous or metamorphic quartz-bearing rocks. This specific specimen has been rounded by fluvial (water) or abrasive mechanical action.
Uses & Applications
Common quartz pebbles are used in construction aggregate, landscaping, road base, and industrial glass-making when high purity.
Geological Facts
Quartz is the second most abundant mineral in Earth's continental crust. Rounded pebbles like this are often indicators of ancient or current riverbeds.
Field Identification & Locations
Identify by its hardness (cannot be scratched by a steel knife) and lack of cleavage. Found globally in streams, beaches, and glacial deposits.
Identified on: 4/29/2026
Mode: Standard