igneous
Polished larvikite tower (often sold as “blue labradorite” or “black moonstone”)
Larvikite, a feldspar-rich monzonite; chiefly alkali feldspar with plagioclase, biotite, and accessory minerals
AI-generated identification · may be incorrectTypically gray to blue-gray with pale feldspar crystals and a silvery-blue sheen; hardness about 6–6.5 Mohs, vitreous to pearly luster, crystalline texture. The image shows a cut and polished specimen; exact identification requires closer inspection.
Identified More igneous →
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Physical properties
Typically gray to blue-gray with pale feldspar crystals and a silvery-blue sheen; hardness about 6–6.5 Mohs, vitreous to pearly luster, crystalline texture. The image shows a cut and polished specimen; exact identification requires closer inspection.
Formation & geological history
An intrusive igneous rock formed as magma cooled slowly beneath the surface, mainly in the Oslo Rift of southeastern Norway, around 300 million years ago.
Uses & applications
Used as dimension stone and decorative facing, as well as for polished carvings and collectible specimens.
Geological facts
Its blue flashes come from light scattering within feldspar crystals, rather than from labradorite composition in most material sold as larvikite.
Field identification & locations
Look for gray feldspar with blue-silver flashes that shift with viewing angle; Norwegian larvikite is especially well known. Similar-looking feldspar-rich stones can be difficult to distinguish by photograph alone.
