metamorphic/igneous

Quartz Vein in Host Rock (Gabbro or Basalt)

Silicon Dioxide (SiO2) with Mafic Silicates

Hardness: 7 (Quartz) / 5-6 (Host); Color: Milky white against dark gray/black; Luster: Vitreous to dull; Crystal structure: Trigonal (hexagonal prisms); Cleavage: None (conchoidal fracture); Specific gravity: 2.65 for white portion.

Hardness: 7 (Quartz) / 5-6 (Host)
Color: Milky white against dark gray/black
Luster: Vitreous to dull

Identified March 12, 2026More metamorphic/igneous →

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Physical properties

Formation & geological history

Formed via hydrothermal activity where silica-rich hot fluids filled fractures in existing country rock during tectonic events. This process can happen across many geological eras from Precambrian to Cenozoic.

Uses & applications

Used primarily as decorative specimens, indicator minerals for gold prospecting, or crushed rock for road base and concrete aggregate.

Geological facts

Quartz veins are the primary source of 'lode gold.' While the white quartz itself is common, its presence often signals that mineralization (including precious metals) has occurred in the surrounding area.

Field identification & locations

Identify by the sharp contrast between the white crystalline band and the dark, fine-grained host rock. Found globally in mountainous regions and gold-bearing belts (e.g., California, Australia, Canada).

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