Cobalt occurs in rocks to the extent of about 0.2 to 250 p.p.m., and is higher in the earlier crystallizing fractions of igneous rocks. A wide variation in cobalt content is found in minerals, from less than 10 p.p.m. in many sulphides to over 8 per cent in rich ores of the Belgian Congo. Arable and pasture soils may contain 0.1 to 430 p.p.m. cobalt. The few data on the occurrence of this element in waters indicate a range from 0.0001 to 13.8 p.p.m. Meteorites may contain 0.005-1.6 per cent cobalt.