Labradorite
Plagioclase Feldspar var. Labradorite · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Triclinic; typically occurs in massive, granular, or blocky habits
Mineral Group
Silicates; Tectosilicate (Feldspar Group)
Chemical Formula
(Ca,Na)(Al,Si)4O8 with trace elements of K, Fe
Formation Process
Igneous formation; crystallizes from cooling magma in gabbro or norite, allowing for the slow exsolution of lamellae.
About This Crystal
A dark, often greyish-green to black mineral that appears opaque to translucent. It features a dull to vitreous luster and is characterized by its internal play of colors (labradorescence).
Physical Characteristics
Color: Dark grey/green; Streak: White; Cleavage: Two directions at nearly 90 degrees; Fracture: Conchoidal to uneven; Specific Gravity: 2.68-2.72; Fluorescence: Occasional weak yellow or blue under UV.
Optical Properties
Refractive Index: 1.560–1.572; Birefringence: 0.008-0.010; Displaying Labradorescence (Schiller effect) caused by light interference in microscopic layers.
Hardness & Durability
Origin Region
Notably Labrador (Canada), Madagascar, Finland (Spectrolite), and Russia; found in mafic igneous rocks.
Hardness & Durability
Mohs Hardness: 6.0–6.5; Toughness: Brittle; Wearability: Good for jewelry but susceptible to scratching and cleavage splits.
Care & Maintenance
Clean with warm soapy water; avoid ultrasonic cleaners, steam, and harsh chemicals. Store separately from harder stones like quartz or sapphire.
Rarity & Value
Common globally, but high-quality specimens with 'full flash' are uncommon. Value is based on the intensity and spectral range of the color flash.
Special Characteristics
Labradorescence is the defining feature, showing metallic tints of blue, green, gold, and violet when tilted in light.
Lore & History
First discovered in Labrador, Canada, in 1770. Inuit lore claims the Northern Lights were trapped inside the rocks. Traditionally associated with the Third Eye chakra and protection.