igneous
White-veined dark stone, likely basalt with quartz/calcite veins
Veined basalt (dark mafic rock; veins likely quartz or calcite)
AI-generated identification · may be incorrectFine-grained, dark gray to black, with white irregular vein fillings and a rounded, water-worn surface; typically hardness 5–6 for basalt, with quartz veins near 7 and calcite near 3. Luster is mostly dull to slightly vitreous; basalt has no visible cleavage.
Identified More igneous →
Explore White-veined dark stone, likely basalt with quartz/calcite veins in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Fine-grained, dark gray to black, with white irregular vein fillings and a rounded, water-worn surface; typically hardness 5–6 for basalt, with quartz veins near 7 and calcite near 3. Luster is mostly dull to slightly vitreous; basalt has no visible cleavage.
Formation & geological history
Basalt formed from rapidly cooled mafic lava, generally in volcanic settings; the white veins formed later when silica- or carbonate-rich fluids filled fractures. Exact geological age cannot be determined from the image.
Uses & applications
Primarily a decorative or collecting stone; basalt is widely used as aggregate, paving, and construction material, while attractive veined pieces may be polished for ornaments.
Geological facts
The contrasting pattern is produced by fracture networks and later mineral precipitation, not necessarily by layering. A vinegar test may fizz if the white material is calcite; quartz will not fizz and scratches glass.
Field identification & locations
Common in volcanic and river environments worldwide, including Iceland, India, the Pacific Northwest, and oceanic crust. Confirm identification with a fresh surface, streak, hardness testing, and acid testing of the white veins.
