mineral

Milky Quartz (Druzy Geode fragment)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent with iron staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent with iron staining
Luster: Vitreous to greasy

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes where silica-rich fluids cool in rock cavities (vugs) or veins. It can occur in all geological ages but is common in ancient igneous and metamorphic terrains.

Uses & applications

Used in the production of glass, ceramics, and abrasives. In collecting, it is popular as a decorative specimen or 'yard rock.' Geodes and druzy clusters are often used in lapidary work and jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. Quartz is piezoelectric, meaning it generates an electric charge in response to mechanical stress.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (H=7) and its lack of cleavage. Look for characteristic crystal points in cavities. Commonly found in riverbeds, mountain ranges, and sedimentary outcrops globally.

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