Fluorine

Fluorine is a base element naturally occurring in the Earth’s crust. It belongs to the halogen group. In the bedrock, fluorine is always found in the form of fluoride, for example as calcium fluoride (fluorite). Fluoride may dissolve in groundwater if the water remains in contact with fluorine-containing minerals for a long time. Excessive fluoride concentrations in well water mainly occur in rapakivi granite areas.