mineral

Bull Quartz (Milky Quartz)

Quartz (Silicon Dioxide - SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to tan with iron staining; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

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

Identified March 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed from hydrothermal veins or as a late-stage crystallization in igneous pegmatites. These specimens are likely 'float' or river-worn cobbles, shaped by erosion over millions of years.

Uses & applications

Industrial use as a source of silicon for semiconductors, manufacturing of laboratory glassware, abrasives, and as decorative stone in landscaping or rustic construction.

Geological facts

Milky quartz gets its characteristic white opacity from tiny bubbles of gas or liquid trapped during crystal growth. It is one of the most common minerals on Earth's crust and is highly resistant to chemical and physical weathering.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife, its heavy weight for its size, and its lacks of distinct cleavage (breaks in curved shards). Often found in dry creek beds or mountainous outcrops.

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