Labradorite
Feldspar group, Plagioclase series (Labradorite variety) · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Triclinic; typically found as massive, granular, or tabular crystals with well-developed cleavage.
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
(Na,Ca)(Al,Si)4O8
Formation Process
Igneous and metamorphic; crystallizes slowly from cooling magma, allowing the microscopic lamellar intergrowths necessary for optical phenomena to form.
About This Crystal
The specimen exhibits a dark, grayish-green to brownish body color with striking flashes of iridescent blue light on its surface. It has a vitreous to pearly luster, is translucent to opaque, and shows characteristic cleavage planes and lamellar twinning striations.
Physical Characteristics
Color is dark gray, brown, or greenish-gray with vibrant labradorescence; white streak; perfect cleavage in two directions intersecting at roughly 86 degrees; uneven to conchoidal fracture; specific gravity around 2.70-2.74; brittle tenacity; generally non-fluorescent.
Optical Properties
Biaxial positive with two refractive indices ranging roughly between 1.559 and 1.568; exhibits strong labradorescence (schiller effect) due to light interference from sub-microscopic lamellar intergrowths.
Hardness & Durability
Origin Region
Madagascar, Finland, Canada (Labrador), Australia, and Mexico; forms in mafic igneous rocks like gabbro and basalt, as well as anorthosites.
Hardness & Durability
Mohs hardness of 6 to 6.5; fair to good toughness, but susceptible to cleavage breakage along specific planes; sensitive to thermal shock and strong acids.
Care & Maintenance
Clean with warm, soapy water and a soft brush; avoid ultrasonic or steam cleaners, harsh chemicals, and prolonged exposure to direct sunlight or sudden temperature changes.
Rarity & Value
Common to uncommon; value depends heavily on the intensity, coverage, and spectrum of the labradorescence flashes (blue, green, gold, purple). Most specimens are untreated.
Special Characteristics
Labradorescence, a specialized form of adularescence characterized by vibrant metallic flashes of color when viewed at specific angles due to light interference.
Lore & History
Discovered on the Isle of Paul in Labrador, Canada, in 1770, and deeply tied to Inuit folklore where it was believed to have fallen from the frozen fire of the Aurora Borealis. In modern crystal healing, it is associated with the throat and third-eye chakras, symbolizing transformation, intuition, and inner strength.