Rainbow Moonstone
Feldspar var. White Labradorite · Semi-Precious Gemstone
Crystal System
Triclinic; typically found in massive, granular, or tabular form
Mineral Group
Silicates (Plagioclase Feldspar subgroup)
Chemical Formula
(Na,Ca)(Al,Si)4O8 with trace Potassium
Formation Process
Igneous; crystallizes from cooling magma in pegmatites, developing its unique layered structure through exsolution
About This Crystal
A colorless to milky white translucent gemstone displaying a characteristic vitreous luster and blue to multicolored adularescence (schiller) when rotated.
Physical Characteristics
Body color is white, streak is white. Cleavage is perfect in two directions at nearly 90 degrees. Specific gravity is 2.62-2.72. Exhibits weak fluorescence in some specimens.
Optical Properties
Refractive Index 1.540-1.553; exhibit adularescence/labradorescence caused by light interference between thin, alternating microscopic layers of albite and orthoclase.
Hardness & Durability
Origin Region
Primarily Sri Lanka, Southern India, Madagascar, and Norway; found in pegmatite and metamorphic deposits
Hardness & Durability
6.0-6.5 on Mohs scale. Brittle toughness; sensitive to pressure and sharp blows due to perfect cleavage.
Care & Maintenance
Clean with warm soapy water and a soft brush only. Avoid ultrasonic and steam cleaners. Store separately to prevent scratching from harder stones like quartz or corundum.
Rarity & Value
Relatively common, but high-quality specimens with strong blue flashes and high transparency are rare and more valuable. Treatments are rare, though some are backed with dark colors.
Special Characteristics
Features 'adularescence,' a blue or rainbow sheen that appears to float across the surface of the stone; may contain 'centipede' inclusions (tiny internal cracks).
Lore & History
Historically used in Roman and Greek jewelry; believed to be made of solidified moonbeams. Traditionally associated with intuition, the divine feminine, and the crown chakra.