Fleur de sel typically has a grain size between 0 and 4 mm (0 and 4000 μm). It is harvested manually from the top layer of the salt pan and is not processed afterwards. As a result, production is considerably limited – which explains why this type of sea salt is relatively expensive compared to coarse sea salt. Its moist and soft grain structure are what sets fleur de sel apart, making it unsuitable for salt mills. Fleur de sel gets its unique structure and characteristic soft taste from its high mineral content (calcium and magnesium). Chefs often turn to fleur de sel to add a finishing touch to their dishes.