Labradorite
Labradorite (Plagioclase Feldspar series) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Triclinic; typically forms as granular or cleavable masses rather than distinct crystals.
Mineral Group
Silicates; Tectosilicate (Feldspar Group - Plagioclase Series)
Chemical Formula
(Ca, Na)(Al, Si)4O8
Formation Process
Igneous; forms in mafic igneous rocks such as basalt and gabbro through magmatic crystallization.
About This Crystal
A dark grayish-green to black mineral that exhibits an iridescent play of colors known as labradorescence. It is translucent to opaque with a vitreous to pearly luster.
Physical Characteristics
Body color is dark gray/green; streak is white; perfect cleavage in two directions; conchoidal to uneven fracture; specific gravity 2.68–2.72; weak fluorescence.
Optical Properties
Biaxial (+/-). Notable for labradorescence, an optical phenomenon caused by light diffracting within lamellar intergrowths of Albite and Anorthite layers.
Hardness & Durability
Origin Region
Labrador (Canada), Madagascar, Finland (Spectrolite variety), Russia, and Australia.
Hardness & Durability
6.0–6.5 on Mohs scale. Brittle tenacity; requires care due to cleavage planes that can split upon heavy impact.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners, steam, and harsh chemicals. Store separately to prevent scratching.
Rarity & Value
Relatively common, though specimens with high-intensity multi-color 'flash' (Spectrolite) or high transparency are more rare and valuable.
Special Characteristics
Labradorescence (iridescence); some specimens may show aventurescence or contain needle-like inclusions of ilmenite or magnetite.
Lore & History
Discovered in Paul's Island, Labrador in 1770. Inuit legend claims the Northern Lights were trapped inside the stones. Traditionally associated with intuition and protection.