igneous

Labradorite (Larvikite variety)

Feldspar (Plagioclase series), (Na,Ca)(Si,Al)4O8

Hardness: 6-6.5 Mohs. Color: Grayish-black with blue/silver labradorescence (schiller effect). Luster: Vitreous to pearly. Crystal system: Triclinic. Specific gravity: 2.68-2.72.

Hardness: 6-6
Luster: Vitreous to pearly

Identified April 10, 2026More igneous →

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Physical properties

Hardness: 6-6.5 Mohs. Color: Grayish-black with blue/silver labradorescence (schiller effect). Luster: Vitreous to pearly. Crystal system: Triclinic. Specific gravity: 2.68-2.72.

Formation & geological history

Formed in plutonic environments from the cooling of magma at depths, resulting in large feldspar crystals. This specific variety is from the Larvik Plutonic Complex in Norway, dating back to the Permian period (approx. 290 million years ago).

Uses & applications

Extensively used as a decorative stone in architecture (façades and countertops), high-end jewelry (cabochons), and as a popular mineral for metaphysical collecting.

Geological facts

The 'blue flash' or labradorescence is not a surface color but a light interference effect from internal sub-microscopic layers created during the cooling of the rock. It is often marketed under the trade names 'Blue Pearl Granite' or 'Black Moonstone'.

Field identification & locations

Identify by rotating the stone in light to catch the metallic blue or silvery internal flashes. It is mostly found in the Larvik region of Norway. Collectors look for high 'flash' density and clarity of the blue hues.

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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)

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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