Quartz Pebble
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 on Mohs scale; Color: Milky white to translucent tan; Luster: Vitreous to waxy (when weathered); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & Geological History
Formed from cooling magma or hydrothermal veins. This specific specimen is a river-worn pebble, meaning its rounded shape was created through mechanical weathering and transport by water over thousands of years.
Uses & Applications
Quartz is used extensively in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative gravel in landscaping.
Geological Facts
Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it often survives as pebbles in riverbeds long after other minerals have decomposed.
Field Identification & Locations
Identify in the field by its hardness (it will scratch glass) and lack of cleavage. Common in riverbeds, beaches, and glacial till worldwide.
Identified on: 4/15/2026
Mode: Standard