Quartz (Milky/Yellowish Pebble)

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to yellowish-tan; Luster: Vitreous (glassy) 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 appears to be a river-worn or water-eroded pebble, likely millions of years old, weathered out of its original host rock.

Uses & Applications

Quartz is used in glassmaking, abrasives, and electronics (due to piezoelectric properties). Pebbles like this are used in landscaping, decorative gravel, or as pocket stones for collectors.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which has ancient origins meaning 'hard'. It is highly resistant to chemical and physical weathering.

Field Identification & Locations

Identify in the field by its hardness (it should scratch glass but cannot be scratched by a steel knife) and its lack of cleavage. It is found globally in riverbeds, beaches, and mountain outcrops. Look for the characteristic 'greasy' or 'waxy' luster on worn surfaces.

Identified on: 4/13/2026

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