igneous

Vesicular Basalt

Mafic Volcanic Rock (Basalt)

Hardness: 6 (Mohs); Color: Dark gray to black; Luster: Dull or earthy; Structure: Vesicular (pitted with gas bubbles); Specific Gravity: 2.8-3.0; Aphanitic texture.

Hardness: 6 (Mohs)
Color: Dark gray to black
Luster: Dull or earthy

Identified April 9, 2026More igneous →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6 (Mohs); Color: Dark gray to black; Luster: Dull or earthy; Structure: Vesicular (pitted with gas bubbles); Specific Gravity: 2.8-3.0; Aphanitic texture.

Formation & geological history

Formed from the rapid cooling of magnesium-rich and iron-rich lava at the Earth's surface. The pits (vesicles) are created by gas bubbles that were trapped as the lava solidified. Primarily found in oceanic crust and volcanic hotspots.

Uses & applications

Commonly used in landscaping as decorative stone, construction aggregate, railroad ballast, and ground into stone wool for insulation.

Geological facts

Basalt is the most common rock type in the Earth's crust and also covers large areas of the Moon, Mars, and Venus. The holes in vesicular basalt can often become filled with secondary minerals like quartz or calcite to form amygdaloids.

Field identification & locations

Identify by its dark color, heavy weight (relative to size), and characteristic swiss-cheese-like holes. Found globally in volcanic regions like Hawaii, Iceland, and the Pacific Northwest.

Other igneous specimens

See all

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous