Fluorite (Rainbow Fluorite)
Fluorite (IMA-approved name) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Cubic (Isometric) system; typically occurs in cubic or octahedral habits, though these specimens are carved/polished heart-shapes
Mineral Group
Halides
Chemical Formula
CaF2 (Calcium Fluoride) with trace Rare Earth Elements (REE) influencing color
Formation Process
Hydrothermal precipitation in veins and cavities from fluorine-rich fluids at low to moderate temperatures.
About This Crystal
Transparent to translucent specimen with distinct color banding (zoning) in shades of green, purple, and teal. Polished into a heart shape with a vitreous (glass-like) luster.
Physical Characteristics
Color: Banded green and purple. Streak: White. Cleavage: Perfect octahedral (four directions). Fracture: Subconchoidal to uneven. Specific Gravity: 3.18. Fluoresces strongly under UV light (usually blue).
Optical Properties
Refractive index is 1.432 to 1.434 (singly refractive). Very low dispersion. Lacks pleochroism due to cubic symmetry.
Hardness & Durability
Origin Region
Notable sources include China, Mexico, England (Blue John), and Illinois (USA). Found in hydrothermal veins and sedimentary deposits.
Hardness & Durability
Mohs hardness of 4 (reference mineral). Poor durability; brittle with perfect cleavage, making it prone to chipping and scratching.
Care & Maintenance
Clean only with warm soapy water and a soft cloth. Avoid ultrasonic cleaners, steam, and harsh chemicals. Store separately from harder stones to prevent scratching and keep away from prolonged sunlight to prevent fading.
Rarity & Value
Common globally, but high-clarity banded specimens are valued collectors' items. Value is based on color saturation and clarity. Generally affordable ($5-$50 for small carvings). Treatments are rare, though some are oiled to hide cracks.
Special Characteristics
Exhibits strong fluorescence under UV light (the phenomenon is named after this mineral). The visible color zoning (bands) represents different stages of growth and trace element concentrations.
Lore & History
Known historically as 'The Most Colorful Mineral in the World.' In traditional lore, it is called the 'Genius Stone,' associated with clarity of thought and the heart/third-eye chakras. Historically used in ancient Egypt and Rome for vessels and ornamental carvings.