mineral

Quartz (Milky/Chalcedony variety)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: Translucent white to tan/yellowish (likely due to iron staining). Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on the Mohs scale
Luster: Vitreous to waxy

Identified July 6, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specimen appears to be water-worn or weathered, common in alluvial deposits and riverbeds. Quartz is ubiquitous across almost all geological ages.

Uses & applications

Used in the manufacturing of glass, ceramics, and abrasives. High-purity quartz is essential in electronics for semiconductors and oscillators. In this rough form, it is common for landscaping or beginner rock collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it generates an electric charge in response to applied mechanical stress, which is why it is used in watches.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage (it breaks in curved, shell-like patterns rather than flat planes). It is found worldwide in mountains, beaches, and deserts.

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