igneous
Basalt with Quartz Veining
Basalt (Mafic Volcanic Rock) with Silicon Dioxide (SiO2) inclusions
Hardness: 6 (Basalt) to 7 (Quartz); Color: Dark grey to black matrix with white or translucent veins; Luster: Dull to glassy when wet; Structure: Fine-grained aphanitic matrix; Cleavage: None (conchoidal fracture)
- Hardness
- 6 (Basalt) to 7 (Quartz)
- Color
- Dark grey to black matrix with white or translucent veins
- Luster
- Dull to glassy when wet
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Physical properties
Hardness: 6 (Basalt) to 7 (Quartz); Color: Dark grey to black matrix with white or translucent veins; Luster: Dull to glassy when wet; Structure: Fine-grained aphanitic matrix; Cleavage: None (conchoidal fracture)
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at the Earth's surface. The white veins are typically formed later by hydrothermal fluids filling fractures, depositing quartz or calcite.
Uses & applications
Used in construction as aggregate, road base, and decorative landscaping. This specific tumbled or river-worn form is used for decorative drainage or as a worry stone.
Geological facts
Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. The white stripes or 'veins' are often nicknamed 'wishing stones' in folklore.
Field identification & locations
Identify in the field by its high density, dark color, and fine-grained texture. Commonly found in volcanic regions, riverbeds, and coastal beaches. Look for the sharp contrast between the dark matrix and white mineral lines.
