With a nuclear microprobe, by exploiting the ¹⁹F (p, xy)¹⁶O reaction, the distribution of fluorine in two dimensions can be readily determined, with a detection limit lower than 50 ppm. New areas of investigation have therefore opened up, two of which are described here. The proton energy was 2.5 MeV, and the 6-7 MeV gamma rays were detected in a large NaI crystal. The radial distribution of fluorine was measured in transverse sections of excavated human and animal bone. In bones which had been exposed to ground water the fluorine concentration at the surface was usually in the range 0.2-1%, and was lower at 3mm depth by a factor 0.1-0.9, depending on the duration of burial. Such profiles show promise as a means of sorting bones of different provenance or age, while further analysis based on diffusion theory may provide a dating technique in the range 0-5000 years. Fluorine concentrations in coexisting minerals were measured in polished thin-sections of igneous and metamorphic rock, and the data used in geothermometric calculations. A short linear scan was made across each selected grain to ensure that a reliable figure was extracted. The simple detection method is vulnerable to interference from several other elements at fluorine levels below about 100 ppm; methods of correction are discussed. -- AATA