Fluorite in Eocene carbonate mudstone of Florida is reported for the first time. Fluorite occurs within primary gypsum nodules at a depth of 235–240 m below the surface. Water chemistry indicates undersaturation for gypsum and fluorite, and their survival is attributed to a lack of groundwater circulation. Fluorite probably formed penecontemporaneously with gypsum in a sabkha environment from seawater-concentrated brine. An additional source of fluoride may have been fluvial transport of salts weathered from Appalachian volcanic rocks.