Fluorite
Fluorite (IMA-approved name) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Cubic (Isometric); habit often includes cubes, octahedrons, and massive or granular aggregates
Mineral Group
Halides
Chemical Formula
CaF2 (Calcium Fluoride) with traces of rare earth metals (Eu, Y, Ce) causing fluorescence
Formation Process
Primarily Hydrothermal, occurring as veins in limestone or associated with metallic ores; also in pegmatites and volcanic environments
About This Crystal
The specimen shows a translucent, crystalline mass exhibiting a brilliant violet-blue fluorescence under UV light. In natural light, fluorite can be purple, green, yellow, or colorless with a vitreous (glassy) luster.
Physical Characteristics
Color: Variable; Streak: White; Cleavage: Perfect octahedral (four directions); Fracture: Subconchoidal to uneven; Specific Gravity: 3.18; Strong violet/blue fluorescence under UV
Optical Properties
Isotropic (Singly Refractive); Refractive Index: 1.433-1.435; Dispersion: 0.007 (very low); Exhibits fluorescence and sometimes phosphorescence
Hardness & Durability
Origin Region
Prominent sources include Southern Illinois and Kentucky (USA), China, England (Blue John), and Mexico
Hardness & Durability
Mohs Hardness: 4; Brittle tenacity; Poor toughness due to perfect cleavage; Low durability for jewelry, best for earrings/pendants
Care & Maintenance
Clean with warm soapy water only; avoid ultrasonic or steam cleaners. Highly sensitive to heat and acids; store separately to prevent scratching from harder minerals
Rarity & Value
Common mineral, but high-quality crystalline specimens or unique colors (like Blue John) are uncommon; Price depends on color saturation and crystal formation ($5 - $500+)
Special Characteristics
Strong UV fluorescence (the term 'fluorescence' is derived from Fluorite); sometimes exhibits thermoluminescence and color zoning
Lore & History
Used by ancient Romans and Egyptians for carving vessels and amulets. Historically termed 'Fluorspar'. Traditionally associated with mental clarity, focus, and the Third Eye chakra in modern crystal lore.