Quartz (Common Quartz Pebble)
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 on Mohs scale; Color: Tan to milky white; Luster: Vitreous to greasy; Crystal Structure: Trigonal (often worn away in pebbles); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & Geological History
Formed from cooling magma or precipitation from hydrothermal veins. This specific specimen is a water-worn or weathered pebble likely eroded from a larger vein and tumbled over time.
Uses & Applications
Common quartz is used in glass making, abrasives, and as a component in concrete and mortar. Higher quality crystals are used in electronics and jewelry.
Geological Facts
Quartz is one of the most abundant minerals in Earth's continental crust. Its name comes from the German word 'quarz', which had its origin in Slavic languages meaning 'hard'.
Field Identification & Locations
Identify by its ability to scratch glass and lack of cleavage. Look for a waxy or glassy luster on fresh breaks. It is ubiquitous in river beds and sedimentary deposits globally.
Identified on: 4/15/2026
Mode: Standard