igneous

Labradorite (Larvikite variety)

Ternary feldspar (Anorthoclase), (Na,K)AlSi3O8

Hardness: 6-6.5 (Mohs scale); Color: Dark grey to black with blue or silver iridescent flashes; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions; Specific Gravity: 2.58-2.62

Hardness: 6-6
Color: Dark grey to black with blue or silver iridescent flashes
Luster: Vitreous to pearly

Identified March 30, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the cooling of magmatic intrusions during the Permian period, approximately 290 million years ago. It crystallizes in deep-seated plutonic environments as a monzonitic rock.

Uses & applications

Extensively used as an ornamental stone in architecture for countertops and building facades. Also popular in jewelry and for decorative polished specimens or palm stones.

Geological facts

Often marketed as 'Blue Pearl Granite' or 'Black Moonstone,' although it is technically a feldspar-rich monzonite. The characteristic blue flash is known as the Schiller effect or labradorescence.

Field identification & locations

Identify by rotating it under light to see internal blue or silver flashes (labradorescence). Most common in the Oslo region of Norway. Collectors should look for high-contrast flashes and minimal cracking.

Other igneous specimens

See all

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

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

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

mineral

Magnetite

Magnetite (Fe3O4)

mineral