Calcite vs Fluorite

Property Calcite Fluorite
Công thức CaCO3 CaF2
Hệ tinh thể Trigonal Cubic (Isometric)
Phân loại khoáng vật 05 Carbonates and Nitrates 03 Halides
Độ cứng Mohs 3.0 4.0
Màu sắc Colorless, white, yellow, orange, blue, green Purple, blue, green, yellow, colorless, pink
Ánh Vitreous Vitreous
Màu vệt White White
Độ trong suốt Transparent Transparent
Cát khai Perfect rhombohedral {1011} Perfect octahedral {111}
Vết vỡ 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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