Quartz Veined Rock (Likely Graywacke or Quartzite)

Physical Properties

Hardness: 7 (veins) / 6-7 (matrix). Color: Grey, white, some greenish oxidation. Luster: Dull matrix with vitreous quartz veins. Crystal structure: Hexagonal/Trigonal (quartz). Cleavage: None (conchoidal fracture). Specific Gravity: 2.6 - 2.7.

Formation & Geological History

Formed through regional metamorphism where heat and pressure recrystallize sedimentary rock. The white veins occur through 'hydrothermal veining,' where mineral-rich hot water fills cracks in the host rock and cools to form quartz.

Uses & Applications

Commonly used as crushed stone in construction, road base, and decorative landscaping. Small rounded specimens are favored by river-rock collectors.

Geological Facts

The presence of these white 'ribbons' of quartz often indicates the rock was subject to intense tectonic stress that fractured the original stone. Many gold deposits around the world are found specifically in these types of quartz veins.

Field Identification & Locations

Identify by looking for a hard, dark matrix intersected by distinct white bands that cannot be scratched by steel. These are very common in glacial till and riverbeds throughout North America and Europe.

Identified on: 4/20/2026

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