Two main theories for the genesis of the skarn ores of Central Sweden are presented — partly, that these were formed through metasomatism by the older granites (Sw.urgraniter), and partly, that they are metamorphic products of sediments deposited during the formation of the Leptite series. Among the principal arguments employed in the discussions, that of the structural peculiarities of the ore bodies was the most important. Few detailed studies of the most common skarn minerals have been carried out. In the present paper the minerals constituting the principal portion of the skarn of the Åsgruvan mine in the Norberg field are described. This has been considered to be a garnet-pyroxeneskarn typical for the Central Swedish iron-ore fields. The Norberg field has been most completely treated by Geijer (1930), who considers the ore of the Åsgruvan mine to have been formed by metasomatic processes.