Bull Quartz

Physical Properties

Hardness: 7 (Mohs scale); Color: Milky white with orange/brown iron oxide staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed from the crystallization of silica-rich hydrothermal solutions in veins or as a late-stage mineral in igneous pegmatites. It is incredibly resistant to weathering, often remaining as 'float' long after the surrounding rock has eroded.

Uses & Applications

Used in the production of glass, ceramics, and abrasives. In construction, it's used for decorative landscaping and as aggregate. High-purity quartz is essential for the electronics industry (silicon wafers).

Geological Facts

Quartz is one of the most abundant minerals in Earth's crust. 'Bull quartz' is a term used by miners for large, milky, non-crystalline veins that often act as indicators for nearby gold deposits in hydrothermal systems.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and waxy/greasy luster on fresh surfaces. It is found globally in almost every geological environment.

Identified on: 4/21/2026

Mode: Standard