Calcite vs Fluorite

Property Calcite Fluorite
Formül CaCO3 CaF2
Kristal Sistemi Trigonal Cubic (Isometric)
Mineral Sınıfı 05 Carbonates and Nitrates 03 Halides
Mohs Sertliği 3.0 4.0
Renk Colorless, white, yellow, orange, blue, green Purple, blue, green, yellow, colorless, pink
Parlaklık Vitreous Vitreous
Çizgi Rengi White White
Şeffaflık Transparent Transparent
Dilimlenme Perfect rhombohedral {1011} Perfect octahedral {111}
Kırılma Conchoidal Conchoidal

Key Differences

  • Calcite (hardness 3) is scratched by a copper coin; fluorite (hardness 4) requires a steel knife to scratch.
  • Calcite reacts vigorously with dilute HCl; fluorite does not react with HCl.
  • Fluorite has perfect octahedral cleavage (4 directions); calcite has perfect rhombohedral cleavage (3 directions).
  • Fluorite (CaF2) is a halide; calcite (CaCO3) is a carbonate.
  • Fluorite fluoresces under UV light (phenomenon named after it); calcite rarely fluoresces.

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