Quartz (Tumbled/Polished Pebble)

Physical Properties

Hardness: 7 (Mohs scale); Color: Pale tan, translucent to milky; Luster: Vitreous (glassy) when polished; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed through the crystallization of silica-rich magma or from hydrothermal veins. This specimen appears to be a water-worn or machine-tumbled stone, likely sourced from sedimentary river deposits or beach gravels where harder quartz remains after softer minerals erode.

Uses & Applications

Aesthetics, decorative vase filler, 'worry stones', or used in jewelry as low-cost beads. Industrial quartz is used in electronics and glass manufacturing.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which means 'hard'.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass easily) and lack of cleavage. This specific shape is characteristic of alluvial transport or tumbling.

Identified on: 4/25/2026

Mode: Standard