mineral

Arfvedsonite

Arfvedsonite [Na3(Fe2+,Mg)4Fe3+Si8O22(OH)2]

Hardness: 5.5-6 (Mohs); Color: Black with blue or green iridescent flashes; Luster: Vitreous to sub-metallic; Crystal Structure: Monoclinic; Specific Gravity: 3.0-3.5

Hardness: 5
Color: Black with blue or green iridescent flashes
Luster: Vitreous to sub-metallic

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 5.5-6 (Mohs); Color: Black with blue or green iridescent flashes; Luster: Vitreous to sub-metallic; Crystal Structure: Monoclinic; Specific Gravity: 3.0-3.5

Formation & geological history

Found primarily in rare alkaline igneous rocks like agpaitic nepheline syenites and granitic pegmatites. It forms during the late stages of magma crystallization.

Uses & applications

Mainly sold as a decorative mineral or pocket stone for collectors; often used by practitioners of crystal healing for its supposed metaphysical properties.

Geological facts

Arfvedsonite was named after the Swedish chemist Johan August Arfwedson, who discovered the element Lithium. It is often confused with Nuummite due to the similar blue-tinged flashes.

Field identification & locations

Can be identified by its dark, almost black body color and the characteristic blade-like flashes of blue/silver seen when rotated under light. Common locations include Greenland, Canada, and Russia.

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Schist

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Epidote

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Gypsum (variety Selenite or Alabaster)

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Mineral

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Mineral/Rock