igneous

Larvikite

Monzonite (intermediate intrusive igneous rock containing plagioclase, alkali feldspar, and minor dark minerals)

Hardness: 6-6.5; Color: Dark grey to bluish-black with silvery or blue sheen; Lustre: Vitreous to pearly; Crystal structure: Monoclinic/Triclinic; Specific gravity: 2.6-2.8; Notable for its schiller effect (Labradorescence).

Hardness: 6-6
Color: Dark grey to bluish-black with silvery or blue sheen

Identified April 4, 2026More igneous →

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Physical properties

Formation & geological history

Formed through the slow cooling of magma deep underground (plutonic) within the Larvik Plutonic Complex in Norway. It dates back to the Permian period, approximately 290 million years ago.

Uses & applications

Extensively used as an ornamental stone in architecture (building facades, countertops), commercial signage, monuments, and as tumbled stones for metaphysical/jewelry purposes.

Geological facts

Also known as 'Black Moonstone' or 'Blue Pearl Granite' despite not being a true granite. It is the national rock of Norway and is famous for the 'blue flash' that occurs when light hits the feldspar crystals at specific angles.

Field identification & locations

Identify by looking for 'schiller' flash in a dark grey matrix. It is commonly found in the Larvik region of Norway. For collectors, look for high contrast between the dark host and the bright blue/silver reflective patches.

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