Quartz Veined Basalt

Physical Properties

Hardness: 6-7 Mohs; Color: Dark grey to green matrix with white/cream veins; Luster: Dull/earthy for matrix, vitreous for veins; Structure: Fine-grained aphanitic matrix with hydrothermal vein filling.

Formation & Geological History

Formed from cooling lava flows (basalt) that subsequently fractured. Hydrothermal fluids rich in silica circulated through these cracks, precipitating quartz and creating the white veins seen today.

Uses & Applications

Used primarily in construction as crushed stone for road bases and concrete aggregate. Attractive specimens are used as garden rocks or educational samples.

Geological Facts

Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floors. The veins in this specimen record the history of tectonic stress that cracked the rock long after it solidified.

Field Identification & Locations

Identified by the dark, heavy, fine-grained host rock contrasted against hard, white, non-reactive veins. Found globally in volcanic provinces and coastal regions.

Identified on: 5/2/2026

Mode: Standard