igneous

Basalt (Vesicular)

Basalt (Extrusive Volcanic Rock)

Hardness: 5-6 (Mohs scale), Color: Dark grey to black, Luster: Dull/Sub-metallic, Crystal Structure: Aphanitic (fine-grained), Cleavage: None (conchoidal fracture), Specific Gravity: 2.8 - 3.0

Identified March 26, 2026More igneous →

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Physical properties

Hardness: 5-6 (Mohs scale), Color: Dark grey to black, Luster: Dull/Sub-metallic, Crystal Structure: Aphanitic (fine-grained), Cleavage: None (conchoidal fracture), Specific Gravity: 2.8 - 3.0

Formation & geological history

Formed from the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon. This specimen appears to have undergone significant water-tumbling, indicating it was likely collected from a riverbed, beach, or stream environment.

Uses & applications

Majorly used in construction (crushed stone) for road base and concrete aggregate. High-quality smooth specimens are often used for hot stone massage therapy or as decorative aquarium/landscaping stones.

Geological facts

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

Field identification & locations

Identify in the field by its dark color, heavy weight (relative to size), and fine-grained texture. To distinguish from chert, check for a duller luster and lack of sharp edges. Often found along coastlines and volcanic mountain ranges.

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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

Blue Apatite

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

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Magnetite

Magnetite (Fe3O4)

mineral