• Highly reactive: Considered one of the most reactive elements. 
   
• Halogen group: Belongs to the halogen group on the periodic table. 
   
• Gas at room temperature: Exists as a pale yellow gas at standard conditions. 

Fluorite, the primary mineral source of fluorine, which gave the element its name, was first described in 1529; as it was added to metal ores to lower their melting points for smelting, the Latin verb fluo meaning 'to flow' gave the mineral its name.  Also derive from fluor (n.) 1660s, an old chemistry term for "minerals which were readily fusible and useful as fluxes in smelting" [Flood], from Latin fluor, originally meaning "a flowing, flow," from fluere "to flow, stream, run, melt"  

Fluor is also the basis for the word fluorspar.  Fluorspar is the commercial name for the mineral fluorite,which is made up of calcium and fluorine. It's a naturally occurring mineral that's found in rocks that have been affected by hydrothermal activity, as well as in some limestone and dolomite deposits. 

• Strengthening enamel

  Fluoride strengthens the enamel, the hard outer surface of teeth. This makes it harder for acid from bacteria to dissolve the tooth's minerals and create cavities.
• Reducing acid production

  Fluoride may reduce the amount of acid produced by bacteria that cause cavities.
• Making it harder for bacteria to stick

  Fluoride may make it harder for bacteria that cause cavities to stick to teeth. 

   

  Fluoride is added to community water supplies and oral care products like toothpaste and mouth rinse. It's also available as a dietary supplement.