Milky Quartz Vein with Iron Staining
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 on Mohs scale; Color: Milky white to translucent with yellowish-brown iron oxide staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
Formation & Geological History
Formed through hydrothermal processes where silica-rich fluids precipitate in rock fractures. Often associated with pegmatites and metamorphic belts. Age can range from Proterozoic to Cenozoic depending on location.
Uses & Applications
Used as a source for silicon in electronics, an abrasive in sandblasting, decorative landscape stone, and occasionally crushed for road base or glass manufacturing.
Geological Facts
Quartz is the second most abundant mineral in Earth's continental crust. Massive white quartz is often called 'bull quartz' in the mining industry and can sometimes be an indicator for gold mineralization in hydrothermal veins.
Field Identification & Locations
Identify by its ability to scratch glass (hardness 7), lack of cleavage, and waxy/crystalline appearance. It is found globally in almost all geological environments, especially in mountain ranges and riverbeds.
Identified on: 4/22/2026
Mode: Standard