Quartz (Milky and Smoky variety)

Physical Properties

Hardness: 7 (Mohs scale); Color: White, tans, translucent to opaque; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; 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 water-worn river pebble, shaped by erosion over thousands of years.

Uses & Applications

Used in the manufacture of glass, ceramics, and abrasives. In this tumbled form, it is common for decorative garden stones, inexpensive jewelry (cabochons), or beginner rock collections.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its white color from tiny pocket inclusions of gas or liquid trapped during crystal growth.

Field Identification & Locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage planes. Found globally in almost all geological environments, particularly in riverbeds and beaches.

Identified on: 4/19/2026

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