Quartz Pebble

Physical Properties

Hardness: 7 (Mohs scale); Color: White, clear, or reddish-brown due to iron staining; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen is a water-worn pebble likely eroded from a larger vein and weathered by river or coastal action over millions of years.

Uses & Applications

Used in glassmaking, electronics (piezoelectric properties), jewelry (semi-precious gems), and as high-strength abrasives.

Geological Facts

Quartz is one of the most abundant and stable minerals on Earth's surface. It can weather into sand but resists chemical breakdown, which is why it often survives as rounded pebbles while other minerals dissolve.

Field Identification & Locations

Identify in the field by its inability to be scratched by steel, glass-like luster on fresh breaks, and lack of cleavage. Common in riverbeds and on beaches worldwide.

Identified on: 4/17/2026

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