Sel gris marin ("grey sea salt") is harvested on the bottom of salt pans during a short period of time from late June to early September. This salt is dyed its natural grey color, thanks to clay from the salt pans. It stores trace elements (calcium, potassium, magnesium, copper, iron, zinc) and minerals, as well as preserves the iodine. This coarse salt is mainly used in cooking foods such as green beans, potatoes, fish and roast "en croute de sel."