Labradorite
Plagioclase Feldspar var. Labradorite · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Triclinic; typically forms in massive, granular, or blocky habits rather than distinct crystals.
Mineral Group
Silicates (Tectosilicate); Plagioclase Feldspar group
Chemical Formula
(Ca,Na)(Al,Si)4O8 (Calcium sodium aluminum silicate)
Formation Process
Igneous formation; crystallizes from cooling magma in plutonic environments like gabbro or norite, or occasionally in metamorphic rocks.
About This Crystal
An opaque to translucent dark gray-green stone. Its most striking feature is its labradorescence—a metallic schiller effect. In this cabochon, the base color is a dark, smoky olive-brown with visible internal cleavage planes and fracture lines.
Physical Characteristics
Color: Dark gray/green base; Streak: White; Cleavage: Perfect in two directions; Fracture: Uneven to conchoidal; Specific Gravity: 2.68–2.72; Luster: Vitreous to pearly.
Optical Properties
Labradorescence (interference of light reflecting from thin microscopic lamellae/intergrowths); Biaxial (+); Refractive Index: 1.560–1.572.
Hardness & Durability
Origin Region
Madagascar, Canada (Labrador), Finland, Norway, and Russia; typically found in mafic igneous rocks.
Hardness & Durability
6.0–6.5 on Mohs scale; Brittle tenacity. Fair durability but prone to scratching or chipping along cleavage planes.
Care & Maintenance
Avoid ultrasonic and steam cleaners. Clean with warm soapy water and a soft cloth. Store separately to avoid scratches from harder stones like quartz.
Rarity & Value
Common to Uncommon. Value is determined by the intensity and spectrum of the labradorescence ('fire'). Rare 'Spectrolite' from Finland displays a full rainbow spectrum.
Special Characteristics
Labradorescence (optical schiller effect); some specimens may show weak fluorescence under UV light or contain black magnetite/ilmenite inclusions.
Lore & History
First discovered in 18th-century Labrador, Canada. Inuit legends claim the stone contains the Northern Lights (Aurora Borealis). In metaphysical lore, it is known as a 'Stone of Transformation' associated with the Third Eye and Crown chakras.