Fluorite mineralization was studied in the Variscan granitoid Karkonosze pluton in the northern part of the Bohemian massif (Lower Silesia, Poland). Fluid inclusions in fluorite and quartz were investigated by the following methods: heating and freezing on an immersion microscope stage, spectrophotometric and electron probe analysis, calcination and water leachate. The parent fluids of fluorite were of the Na-Ca-Cl type with a low CO₂ content. The fluoride ions had sources in the pluton and in its host rocks. Fluid inclusion observations provide evidence of various post-formation alteration. such as refilling, partition, cracking, migration, expulsion or vacuole modification from irregular to cubic habit. A final model of fluorite origin and parent fluid evolution is presented.
