Quartz (River Pebble)

Physical Properties

Hardness: 7 on Mohs scale. Color: Translucent white to tan/yellow with iron staining. Luster: Vitreous to waxy after weathering. Crystal structure: Trigonal/Hexagonal. Cleavage: Indistinct (conchoidal fracture). Specific Gravity: 2.65.

Formation & Geological History

Formed from silica-rich hydrothermal solutions or cooling magma. This specific specimen has been shaped and rounded by fluvial processes (water erosion in a river or stream) over thousands of years.

Uses & Applications

Used in industry for glass making, electronics (oscillators), abrasives, and as decorative gravel in landscaping or aquariums.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. River quartz pebbles are often used by ancient humans to create stone tools due to their predictable fracturing and hardness.

Field Identification & Locations

Identify by its hardness (it will scratch glass) and lack of cleavage. Found globally in riverbeds, beaches, and glacial deposits. For collectors, look for clarity or unique inclusions.

Identified on: 4/25/2026

Mode: Standard