igneous

Basalt with Garnet inclusions

Basalt containing Nesosilicate (Garnet Group, likely Almandine Fe3Al2Si3O12)

Hardness: 6.5-7.5 (garnets) vs 5-6 (basalt matrix); Color: Dark grey to reddish-brown; Luster: Vitreous to dull; Structure: Crystalline inclusions in an aphanitic host; Specific Gravity: 3.0-4.3

Hardness: 6
Color: Dark grey to reddish-brown
Luster: Vitreous to dull

Identified April 12, 2026More igneous →

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Physical properties

Hardness: 6.5-7.5 (garnets) vs 5-6 (basalt matrix); Color: Dark grey to reddish-brown; Luster: Vitreous to dull; Structure: Crystalline inclusions in an aphanitic host; Specific Gravity: 3.0-4.3

Formation & geological history

Formed from rapid cooling of magnesium-rich and iron-rich lava. The garnet crystals typically form under high pressure and temperature conditions within the earth's crust or mantle before being transported to the surface by basaltic magma.

Uses & applications

Used primarily for geological study and mineral collecting. Basalt is common in construction (crushed stone), while garnets are used as abrasives or semi-precious gemstones.

Geological facts

Garnets are found in deep-seated volcanic rocks called 'xenocrysts' when they don't originate from the magma itself but are picked up along the way.

Field identification & locations

Identify by looking for glassy, reddish-brown dodecahedral crystals embedded in a dark, fine-grained volcanic matrix. Found in volcanic regions like the American Southwest, India, and Brazil.

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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

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

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

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Magnetite

Magnetite (Fe3O4)

mineral