igneous
Quartz-veined Basalt or Diabase Pebble
Igneous rock with hydrothermal quartz vein
Hardness: 6-7 (due to the quartz vein), 5-6 for the host rock; Color: Dark grey to black with a prominent white mineral vein; Luster: Dull to vitreous on the vein; Crystal structure: Microcrystalline to cryptocrystalline host with crystalline quartz.
- Hardness
- 6-7 (due to the quartz vein), 5-6 for the host rock
- Color
- Dark grey to black with a prominent white mineral vein
- Luster
- Dull to vitreous on the vein
Identified More igneous →
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Physical properties
Hardness: 6-7 (due to the quartz vein), 5-6 for the host rock; Color: Dark grey to black with a prominent white mineral vein; Luster: Dull to vitreous on the vein; Crystal structure: Microcrystalline to cryptocrystalline host with crystalline quartz.
Formation & geological history
Formed via cooling and solidification of molten rock (magma/lava) to form a dark igneous base, followed by later geological fracturing and hydrothermal fluid deposition filling the crack with quartz.
Uses & applications
Used primarily as a decorative stone, lapidary cabochons, or educational geological specimen.
Geological facts
Vein-filled pebbles like this are often smoothed and rounded by water action in rivers or coastal environments, making them popular finds for beachcombers and rockhounds.
Field identification & locations
Easily identified in the field by contrasting white mineral veins (typically quartz or calcite) cutting sharply through a dark, fine-grained host rock.
