Fluorite
Fluorite (Calcium Fluoride) · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Cubic (Isometric); typically forms as cubes, octahedrons, or massive/granular habits.
Mineral Group
Halides
Chemical Formula
CaF2 (Trace elements like Europium or Yttrium cause the fluorescence)
Formation Process
Primarily hydrothermal; forms from circulating hot, fluorine-rich fluids in limestone cavities or as a gangue mineral in metallic ore veins.
About This Crystal
Visible in the image is a translucent to transparent crystalline cluster exhibiting a strong bluish-purple response to UV light. The surface shows distinct cleavage planes and a vitreous (glass-like) luster, typical of cubic crystals.
Physical Characteristics
Color: Variable (purple, green, yellow, clear) but shows blue/violet under UV. Streak: White. Cleavage: Perfect octahedral in four directions. SG: 3.18. Tenacity: Brittle.
Optical Properties
Isotropic (singly refractive). RI: 1.434. Very low dispersion. Notable for intense fluorescence (it is the namesake for the word 'fluorescence').
Hardness & Durability
Origin Region
Major sources include the UK (Blue John), China, Mexico, Morocco, and Illinois (USA). Found in hydrothermal veins and sedimentary environments.
Hardness & Durability
Mohs Hardness: 4. Very fragile; sensitive to heat and pressure. Not recommended for rings due to low hardness and easy cleavage.
Care & Maintenance
Clean with warm soapy water only. Avoid ultrasonic cleaners, steam, and acids. Store separately from harder minerals to prevent scratching. Can fade in prolonged sunlight.
Rarity & Value
Common globally, but high-clarity color-zoned or unique fluorescent specimens are valued by collectors. Often heat-treated or oiled to enhance clarity.
Special Characteristics
Displays strong blue to violet fluorescence under long-wave UV light due to trace Europium ions. Also known for thermoluminescence (glowing when heated).
Lore & History
Historically used by ancient Egyptians and Romans for vessels and amulets. In traditional lore, it is called the 'Genius Stone,' associated with mental clarity, focus, and the Third Eye chakra.