igneous

Basalt with Quartz Veins

Mafic Igneous Rock (primarily Plagioclase and Pyroxene) with SiO2 inclusions

Hardness: 6-7 Mohs; Color: Dark grey to black matrix with white/yellowish linear veins; Luster: Dull to sub-metallic; Structure: Fine-grained aphanitic matrix; Cleavage: None (conchoidal fracture)

Hardness: 6-7 Mohs
Color: Dark grey to black matrix with white/yellowish linear veins
Luster: Dull to sub-metallic

Identified May 25, 2026More igneous →

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Physical properties

Hardness: 6-7 Mohs; Color: Dark grey to black matrix with white/yellowish linear veins; Luster: Dull to sub-metallic; Structure: Fine-grained aphanitic matrix; Cleavage: None (conchoidal fracture)

Formation & geological history

Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the Earth's surface. The veins were formed later when silica-rich hydrothermal fluids filled fractures in the cooling rock.

Uses & applications

Primarily used as decorative river stones, landscaping, or as an aggregate in construction. High-quality smooth specimens are used in 'worry stones' or meditation sets.

Geological facts

Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. The white stripes are evidence of ancient seismic or tectonic activity that cracked the rock, allowing mineral-rich water to seep in.

Field identification & locations

Identify in the field by its dark, heavy feel and characteristic 'stripe' crossing the body of the stone. Commonly found in riverbeds, glacial tills, and coastal areas.

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

Blue Apatite

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

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Magnetite

Magnetite (Fe3O4)

mineral