Fleur de sel ("Flower of salt" in French) is a hand-harvested sea salt collected by workers who scrape only the top layer of salt before it sinks to the bottom of large salt pans. Traditional French fleur de sel is collected off the coast of Brittany (most notably in the towns of Guérande - Fleur de Sel de Guérande, hand harvested from salt marsh water being the most revered), Noirmoutier, and also Camargue. It is often slightly grey due to the sandy minerals collected in the process of harvesting the salt from the pans. On occasion, the presence of Dunaliella salina (a type of pink microalgae commonly found in salt marshes) can give it a light pink tint. Due to its relative scarcity, Fleur de sel is one of the more expensive salts. It is usually sold in airtight jars as it is slightly damp.