Quartz (Milky/Yellowish variety)

Physical Properties

Hardness: 7 on Mohs scale; Color: Milky white to pale yellowish-tan; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & Geological History

Formed from the cooling of silica-rich magma or from hydrothermal veins. It is one of the most abundant minerals in the Earth's crust and can be found in rocks from nearly all geological ages.

Uses & Applications

Used in glassmaking, as an abrasive, in electronics (due to piezoelectric properties), and occasionally as a semi-precious gemstone or decorative 'river rock'.

Geological Facts

Quartz is one of the hardest common minerals, making it resistant to weathering. The milky appearance is caused by minute fluid 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. It is commonly found in gravel pits, mountain streams, and as veins in larger rock outcrops.

Identified on: 4/22/2026

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