Labradorite (Spectrolite variety)
Plagioclase Feldspar var. Labradorite · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Triclinic; typically occurs in massive or granular crystal habits with common polysynthetic twinning
Mineral Group
Silicates (Tectosilicates); Plagioclase Feldspar Group
Chemical Formula
(Ca,Na)(Al,Si)4O8 with various trace elements such as iron and titanium
Formation Process
Igneous formation via crystallization from cooling magma in plutonic environments; also found in certain metamorphic rocks through regional metamorphism
About This Crystal
An opaque to translucent dark grey or black mineral base that exhibits a brilliant play of iridescent colors (labradorescence) including blue, gold, and green. Features a vitreous to pearly luster and often shows internal fractures and lamellar twinning lines.
Physical Characteristics
Dark grey to black body color; white streak; perfect cleavage in two directions at nearly 90 degrees; conchoidal to uneven fracture; specific gravity of 2.68-2.72; non-magnetic; may show weak fluorescence under UV
Optical Properties
Refractive index 1.560-1.572; biaxial positive; exhibits labradorescence (Schiller effect) caused by light scattering in microscopic exsolution lamellae
Hardness & Durability
Origin Region
Madagascar, Labrador (Canada), Finland (Spectrolite), and Russia; commonly found in mafic igneous rocks like basalt and gabbro
Hardness & Durability
Mohs hardness of 6.0 to 6.5; brittle toughness; sensitive to sudden temperature changes and pressure due to distinct cleavage planes
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic or steam cleaners; protect from hard impacts which may cause splitting along cleavage planes; store away from harder gems like sapphires
Rarity & Value
Common globally but high-quality iridescent specimens are uncommon; Spectrolite from Finland is the most valuable; prices vary based on the intensity and spectrum of the color flash
Special Characteristics
Labradorescence is the primary feature, often showing a full spectrum of colors; may contain needle-like mineral inclusions or display a phantom effect within the layers
Lore & History
Inuit legend claims the Northern Lights were trapped inside rocks along the coast of Labrador; modern metaphysical beliefs associate it with the Third Eye chakra, transformation, and protection from negative energy