igneous

Basalt with Quartz/Calcite Veins

Extrusive mafic igneous rock with hydrothermal mineralization

Hardness: 5-6 (base rock), 7 (veins); Color: dark gray to black matrix with white/yellowish veins; Luster: dull to earthy (matrix), vitreous (veins); Structure: fine-grained (aphanitic); Cleavage: none (conchoidal fracture).

Hardness: 5-6 (base rock), 7 (veins)
Color: dark gray to black matrix with white/yellowish veins
Luster: dull to earthy (matrix), vitreous (veins)

Identified May 24, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the Earth's surface. The veins formed later through hydrothermal activity where mineral-rich hot water filled cracks in the solidified basalt.

Uses & applications

Basalt is used extensively in construction (aggregate, pavement), while veined specimens are popular as decorative stones and for educational geological collections.

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

Identified by its heavy weight, dark color, and fine texture. Veins indicate post-volcanic tectonic or hydrothermal stress. Commonly found in volcanic fields, oceanic islands, and mid-ocean ridges.

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

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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)

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Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Magnetite

Magnetite (Fe3O4)

mineral