Delavignes Sel de Guerande is also known as French Grey Sea Salt. The French are the first known to harvest sea salt; records age back to the 7th century and to this day they still hand harvest it in the same traditional “Celtic” way. Salt is harvested by drying seawater in shallow pools. As the water evaporates, the remaining salt is moved around with salt rakes and formed into small pyramids. It is the top of the salt pyramid that dries first and is considered the best.