Quartz (specifically Milky/Gray Quartz vein)

Physical Properties

Hardness: 7 on Mohs scale; Color: Translucent gray to milky white; Luster: Vitreous to waxy when weathered; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Formed from hydrothermal solutions or cooling magma in veins within other rock bodies. This specimen appears water-worn or weathered, likely formed during the Precambrian or Paleozoic eras and subsequently eroded into its current rounded shape.

Uses & Applications

Used in glassmaking, abrasives, silicon production for electronics, and as a durable material in construction and landscaping. Also collected as a hobbyist mineral.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezo-electric, meaning it generates an electric charge when mechanically stressed, which is why it is used in watches.

Field Identification & Locations

Identify by its ability to scratch glass (hardness 7) and its lack of cleavage. Commonly found in riverbeds, gravel pits, and mountain ranges globally. It is very resistant to chemical and physical weathering.

Identified on: 4/27/2026

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