What is "fleur de sel"

n. Floating salt crystals skimmed from the surface of evaporating ponds.

Fleur de sel ("flower of salt" in French; ) or flor de sal (also "flower of salt" in Portuguese, Spanish and Catalan) is a salt that forms as a thin, delicate crust on the surface of seawater as it evaporates. Fleur de sel has been collected since ancient times (it was mentioned by Pliny the Elder in his book Natural History), although it was traditionally used as a purgative and salve. It is now used as a finishing salt to flavor and garnish food. The name comes from the salt's faint aroma of violets.