igneous

Basalt River Stone

Extrusive mafic igneous rock

Hardness (6 on Mohs scale), color is dark grey to black, luster is dull to waxy when wet, fine-grained phaneritic structure, high specific gravity (heavy for its size).

Identified May 25, 2026More igneous →

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Physical properties

Hardness (6 on Mohs scale), color is dark grey to black, luster is dull to waxy when wet, fine-grained phaneritic structure, high specific gravity (heavy for its size).

Formation & geological history

Formed from the rapid cooling of magnesium-rich and iron-rich lava at the earth's surface. This specific specimen has been smooth-tumbled by water action in a river or coastal environment over thousands of years.

Uses & applications

Used in landscaping, high-end construction (as pavers or tiles), hot stone massage therapy, and as decorative gravel.

Geological facts

Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. It is also found on the Moon and Mars.

Field identification & locations

Identify by its dark color, heavy weight, and absence of visible crystals. It is commonly found in volcanic regions, riverbeds, and along shorelines. Collectors look for unique shapes or 'omars'.

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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