Fleur de Sel is made of the fine, light crystals that float on the surface of salt pans. It is hand-harvested by workers who scrape only the top layer of salt before it sinks to the bottom of large salt pans.
Its special flavour comes partly from the presence of Dunaliella salina (a type of pink micro algae found in salt marshes).
Due to its relative scarcity, Fleur de Sel is one of the most expensive salts, and Fleur de Sel de Guérande (Brittany, France) is one of the most renowned in the world. Fleur de Sel de Guérande comes in a lovely jute bag.