Milky Quartz

Silicon Dioxide (SiO2)

Rock Type: mineral

Milky Quartz

Physical Properties

Hardness: 7 (Mohs scale); Color: White to translucent gray with tan/yellow staining; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & Geological History

Formed through hydrothermal processes, cooling of magma in pegmatites, or metamorphism. It can be found in vein deposits or as masses. Quartz is incredibly stable and persists as other rocks weather away.

Uses & Applications

Used in glassmaking, abrasives, jewelry (cabochons), electronics (oscillators), and construction as aggregate. Large specimens are popular for garden landscaping and crystal collecting.

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.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass and steel), white/cloudy appearance, and lack of cleavage. Commonly found in riverbeds, mountains, and as 'veins' in granite outcrops.

Identified on: 4/20/2026

Mode: Standard