igneous

Vesicular Basalt (Lava Rock)

Basalt (Vesicular Variety)

Hardness: 5-6 Mohs; Color: Grey, brown, or reddish-brown (weathered); Luster: Dull or earthy; Crystal structure: Aphanitic (fine-grained); Texture: Vesicular (contains many small pits or cavities called vesicles); Specific gravity: 2.8-3.0.

Hardness: 5-6 Mohs
Color: Grey, brown, or reddish-brown (weathered)
Luster: Dull or earthy

Identified May 23, 2026More igneous →

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Physical properties

Formation & geological history

Formed through the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon. The holes (vesicles) are created by gas bubbles that were trapped in the lava as it solidified.

Uses & applications

Commonly used in landscaping as decorative ground cover, in gas grills to distribute heat (lava rocks), as an abrasive in some industrial processes, and sometimes as a lightweight aggregate in construction.

Geological facts

Vesicular basalt is the most common rock type on the surface of the Moon and Mars. When the vesicles are extremely dense and the rock can float on water, it is instead classified as scoria or pumice.

Field identification & locations

Identify by its 'pock-marked' appearance resembling a sponge but with a dense, stony weight. Can be found in volcanic fields, near oceanic ridges, and active or extinct volcanoes worldwide.

Other igneous specimens

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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

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral