igneous

Labradorite (Larvikite variety)

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

Hardness: 6-6.5 Mohs. Color: dark grey to black with blue or silver flashes (labradorescence). Luster: vitreous to pearly. Crystal structure: triclinic. Cleavage: perfect in two directions.

Hardness: 6-6
Luster: vitreous to pearly

Identified April 12, 2026More igneous →

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Physical properties

Hardness: 6-6.5 Mohs. Color: dark grey to black with blue or silver flashes (labradorescence). Luster: vitreous to pearly. Crystal structure: triclinic. Cleavage: perfect in two directions.

Formation & geological history

Forms in mafic igneous rocks through slow cooling of magma within the Earth's crust. Most high-quality specimens, like the Larvikite shown here, are from the Permian period approximately 290 million years ago.

Uses & applications

Used extensively in jewelry for its iridescent qualities, as well as interior design for countertops, tiles, and high-end architectural cladding.

Geological facts

The iridescent effect is known as 'labradorescence' or 'Schiller effect,' caused by light diffracting between microscopic layers of different mineral compositions within the stone.

Field identification & locations

Identify by rotating it under a light source to find the metallic 'flash' or blue/silver sheen. Found commonly in Norway (Larvik region), Madagascar, and Canada (Labrador).

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

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

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

mineral

Magnetite

Magnetite (Fe3O4)

mineral