igneous
Basalt with Quartz Vein
Basalt (fine-grained mafic igneous rock) with crystalline Quartz (SiO2)
Hardness: 6-7 (Mohs); Color: Dark green to charcoal grey matrix with a white/milky opaque band; Luster: Dull/earthy for the basalt, vitreous/glassy for the quartz; Crystal structure: Aphanitic (basalt) and Hexagonal (quartz).
- Hardness
- 6-7 (Mohs)
- Luster
- Dull/earthy for the basalt, vitreous/glassy for the quartz
Identified More igneous →
Explore Basalt with Quartz Vein in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs); Color: Dark green to charcoal grey matrix with a white/milky opaque band; Luster: Dull/earthy for the basalt, vitreous/glassy for the quartz; Crystal structure: Aphanitic (basalt) and Hexagonal (quartz).
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the surface. The white vein formed later via hydrothermal activity, where mineral-rich hot water filled cracks in the rock and precipitated quartz crystals.
Uses & applications
Basalt is used for road base, concrete aggregate, and railroad ballast. The specimen itself is primarily used for educational purposes or as a garden/lapidary stone.
Geological facts
Quartz veins are often indicators for mineral prospectors as they can sometimes contain gold or other precious metals deposited by the same hydrothermal fluids.
Field identification & locations
Identify in the field by its high density, dark color, and the presence of a hard white vein that cannot be scratched by a steel knife. Common in volcanic regions or oceanic crust formations.
