Quartz Pebble

Physical Properties

Hardness: 7 (Mohs scale), Color: White to yellowish-tan, Luster: Vitreous to waxy (when river-worn), Crystal Structure: Trigonal, Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65

Formation & Geological History

Formed from silica-rich hydrothermal veins or cooling magma. These specific specimens are river-worn or ocean-tumbled pebbles that have been rounded by water erosion over hundreds to thousands of years.

Uses & Applications

Used in landscaping, aquariums, glass manufacturing, electronics (due to piezoelectric properties), and as decorative masonry stones.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to both chemical and mechanical weathering, which is why it often remains as pebbles after other minerals have eroded away.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass) and its lack of cleavage. Look for smooth, rounded shapes in riverbeds or on beaches with common iron-oxide staining (yellow/orange tints).

Identified on: 4/19/2026

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